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<APU 1 1886 



WARM-BLAST 



STEAM-BOILER FURNACE 



WARM-BLAST 



STEAM-BOILER FURNACE. 



A REPORT UPON A SERIES OF TRIALS OF AN APPARATUS 

FOR TRANSFERRING A PART OF THE HEAT OF 

ESCAPING FLUE-GASES TO THE FURNACE 

BY WARMING THE ENTERING AIR. 



BY 

J. O. HOADLEY. 



Of 




NEW YORK: 
JOHN WILEY & SONS. 



1886. 



^ 




A^S/i 






COPTRIGHT, 1886, 

By J. C. HOADLEY. 



c ^ b & 



Press of J. J. Little & Co., 

Nos. 10 to 20 Astor Place, New York. LC Control Number 



■111 



tmp96 027066 



CONTENTS. 



i. 

PAGE 

Preface and Introduction 1 

Object of the Experiments 3 

Points Covered by the Investigation 4 

Method of Conducting the Experiments 6 

Analyses of Coals 8 

Description of Boilers 8 

Description of Boiler Plant 12 

Description of Warm Blast Apparatus 14 

II. 

Description of Instruments 27 

The Pyrometer 27 

The Calorimeter 40 

The Anemometer 50 

The Incased Aneroid 53 

The Mercurial Barometer 51 

The Hygrometer 54 

Thermometers 54 

The Winclder Apparatus 55 

The Geissler Bulbs 55 

The Chemical Balance 55 

The Steam Gauge 56 

The Edson Pressure Recording Gauge 56 

III. 

General Summary of Results 57 

IV. 

Condensed Records of Weekly Experiments 60 

Analysis of Coal, in Detail 74 

Analysis of Dry Fuel Gases, Days 75 

Analysis of Dry Fuel Gases, Nights 76 

Pyrometric Measurements of Temperatures 77 

Calorimetric Observations to Determine the Quality of Steam 90 

Continuous Analysis of Flue Gases 112 

Ashes and Residue 126 

Boiler Pressure by Steam Gauge 129 

Capacity of Boiler at Various Heights of Water Level and at Various 

Pressures 133 



Vlll CONTENTS. 

PAGE 

Condensed Records of Weekly Experiments : 

Radiation from Brick-work 134 

Transmission of Heat through Brick-work 140 

Power Consumed in Driving- Blower 150 

Solid Carbon and Ash in Flue Gases 155 

Appendix A, Contract for the Experiments • 156 

Appendix B, Combustion of Coal, by J. C. Hoadley 158 

Appendix C, Patents, 0. Marland's and others 168 



LIST OF ILLUSTRATIONS. 



NO. PAGE 

1. Ground-plan of Boiler-house. 11 

2. Cross-section of warm-blast boiler No. 1, through furnace 14 

3. Vertical, longitudinal section of warm-blast boiler No. 2 16 

4. Vertical, longitudinal section of warm-blast boiler No. 2, showing the 

deflectors of the abstractors 21 

5. Cross-section of warm-blast boiler No. 1, at Pier; but showing the ab- 

stractors of No. 2 22 

6. Water- platinum Pyrometer 27 

7. Platinum balls, crucibles and fire-brick bed and cover, as arranged for 

use with the Water-platinum Pyrometer 37 

8. Top view of lower fire-brick 37 

9. Calorimeter, section of 41 

10. Apparatus for testing the heat-capacity of the Calorimeter 45 

11. Anemometer 50 

12. Graphic representation of Table XVIII., p. 80 81 

13. Graphic representation of part of Table XVIII., Pacific Boiler, July 14, 

1881 82 

14. Diagram of Comparative Temperatures 86 

15. Diagram of Temperatures, Volumes and Surfaces 89 

16. Mixing-box for obtaining samples of flue-gases for analysis 113 

17. Apparatus for continuous analysis of flue-gases by the gravimetric. . . . 

method 114 

18. Apparatus for absorption of C0 2 from flue-gases, for conversion of . . . . 

CO into C0 2 , and for the absorption of the resulting C0 2 , in the con- 
tinuous analysis of flue-gases 116 

19. Diagram of Carbon Monoxide produced by excessively rapid firing: 

graphical representation of Table XXVI 119 

20. Ore Sampler, for obtainiug samples of ashes and residue 127 

21. Diagrams of Boiler-pressure, reduced from the diagrams of Edson's 

Pressure Recording Gauge 129, 130. 131 

22. Horizontal section of brick-work of warm-blast boiler No. 1, showing 

the location of holes for taking temperatures 140 

23. Graphical representation of Table XXX 142 

24. Graphical representation of Table XXX., arranged continuously , 143 

25. Graphical representation of Table XXXI. ; temperatures in brick-work 143 

26. Graphical representation of Table XXXI.; temperatures in brick-work 143 

27. Actual hourly temperatures in brick- work ; Table XXXI 145 

28. Quarter-hourly actual temperatures in brick- work ; Table XXXI 145 

29. Graphical representation of Table XXXII. ; temperatures in brick- work 145 

30. Hourly mean transverse temperatures in brick- work ; Table XXXII 145 

31. Hourly actual temperatures in brick-work ; Table XXXII 147 



X LIST OF ILLUSTRATIONS. 

NO. PAGE 

32. Graphical representation of extreme temperatures in brick-work ; 

Table XXXII 147 

33. Actual quarter-hourly temperatures in brick-work ; Table XXXII 148 

34. Indicator Diagram, Engine -driving Blower, exhausting into the air 150 

35. Indicator Diagram, Engine-driving Blower, exhausting into a surface 

condenser 150 

36. Mean Indicator Diagram, Engine-driving Blower, exhausting into a 

surface condenser 151 



LIST OF TABLES. 



TABLE PAGE 

I. Summary of Analysis of Coals. 8 

II. Temperatures, Fahrenheit, and corresponding number of British 

Thermal Units contained in water, from zero Fahrenheit 32' 

III. Correction-table for varying specific beat of Platinum, 0° to4C00° 

F 35, 36 

IV. Correction-table for varying Specific Heat of Iron, 0° to 2000° F. . . 38 
V. Correction- table for varying Specific Heat of a Heat-carrier com 

posed of equal weights of Iron and Platinum 39 

VI. Effective Heat Value of the Calorimeter 44 

VII. Errors of Pouring in, Drawing out, and Weighing 45 

VIII. Determination of the Heat-capacity of Calorimeter 47 

IX. Quantities of Heat in British Thermal Units 48 

X. General Summary of Results 57 

XL Condensed Record of Weekly Experiments 62 to 72 

XII. Condensed Record of Weekly Experiments : Details of Analysis of 

Coals 74 

XIII. Atmospheric Air 74 

XIV. Analysis of Dry Flue-gases, Days 75 

XV. Analysis of Dry Flue-gases, Nights 76 

XVI. Pyrometric Observations of Temperatures at Warm-blast Boiler 

No. 1, at Bridge- wall, and in the Heart of the Fire 78 

XVII. Temperatures deduced from Pyrometric Observations in Table 

XVI. , by the second and third methods, as described on p. 45. . . 79 
XVIII. Temperatures at Bridge-wall, ascertained by the use of the "Water- 
platinum Pyrometer 80 

XIX. Pyrometric Measurements of Temperatures in Arch over Warm- 
blast Boiler No. 1 83 

XX. Comparison of Temperatures found in Pacific and Warm-blast 

Boilers 83 

XXI. Comparative Temperatures : Pacific and Warm-blast Boilers un- 

der equal conditions 87 

XXII. Calometric Observations 91 to 104 

XXIII. Heat lost by Steam and gained by "Water 106 

XXIV. Reductions of Calometric Observations 107 to 110 

XXV. Limits of Error in Calometric Work 112 

XXVI. Carbon Monoxide produced by excessively rapid firing 120 

XXVII. Capacity of Boiler in pounds of Water for each inch in height 
from to 10 inches, and for each 5 pounds of Steam-gauge 

Pressure from to 80 pounds 135, 136 

XXVIII. Radiation : Experiment No. 1 137 

XXIX. Radiation : Experiment No. 2 138 



Xll LIST OF TABLES. 

TABLE PAGE 

XXX. Temperatures of Brick-work : warm-blast boiler setting No. 1, 
12' 5" from front end, — 2' 5" above grates, — 28" from out- 
side, — 4.5 " from inside of side wall 141 

XXXI. Temperature of Brick-work : warm-blast boiler setting No. 1, at 
various depths, namely, 8 inches, 16 inches, and 24 inches 

from the outer surface 144 

XXXII. Temperatures of Brick-work : warm-blast boiler setting No. 1, at 
various depths, namely, 4 inches, 16 inches, and 28 inches from 
the outer surface 146 



CLXXXIII. 

REPORT OF A SERIES OF TRIALS OF A WARM-BLAST 
APPARA TUS, FOR TRANSFERRING A PART OF THE 
HEAT OF ESCAPING FLUE GASES TO THE FUR- 
NACE. 

BY J. C. HOADLET, BOSTON, MASS. 

The experiments of which an account will be found in the fol- 
lowing paper were begun in the summer of 1881, and, with the 
interruptions required for the modifications of the apparatus, occu- 
pied nearly a year. They were conducted at the chemical works of 
the Pacific Mills, Lawrence, Mass., by Mr. Fred. II. Prentiss, under 
the direction of the writer. Ever since the conclusion of the last 
weekly experiment, May 20, 1882, the apparatus has been in un- 
interrupted use, and appears to be still in good order, with fair indica- 
tions of reasonable durability — a point to be settled only by continued 
use. A number of causes have delayed the publication of this report : 
the unusual scope of the experiments, the great length of the boiler 
tests — embracing nine full weeks — the. number of subjects investi- 
gated, the attempt to ascertain everything which could affect the 
result — taking for granted nothing but the well-established phys- 
ical laws concerned — have resulted in a large mass of notes which 
required much labor for their proper digestion. Its publication has 
been still further delayed — not unwisely, perhaps — in order to gain, 
by experience in practical use, some knowledge of the advantages 
and disadvantages of the apparatus, as time alone can reveal them. 

The teachings of these experiments are little less valuable on 
their negative than on their positive side. It is hardly less worth 
while to know the absolute limitations of economy in coal combus- 
tion ; to know what cannot be done, though quacks promise never 
so largely, as to learn by what means some part of the important 
loss of heat inevitable with existing arrangements, may be arrested 
and put to use at reasonable cost and without undue trouble or in- 
convenience. 

On both these points, it is believed, some contributions of real 
value will be found in this paper. Much, perhaps most of it, is only 
confirmatory of facts previously known ; but in some respects these 
are here based on broader, more complete and longer-continued ex- 
periments, with the aid of some new instruments. Single boiler tests, 



2 TEIALS OF A WARM-BLAST APPARATUS. 

as boiler tests are usually conducted, are of very limited value. Too 
many unfounded assumptions are usually made. "Coal "is taken 
as equal to something to be found in tables, sometimes even with- 
out allowing for surface moisture, which may be dried out ; yet 
there is more difference in coal than there is in boilers, rejecting 
boilers notoriously defective, and surface water will range all the 
way from 0.5 per cent, to 8 per cent. " Steam " is taken as of fixed 
and standard quality, as if it were dry, saturated steam, which is 
possible only when no steam is drawn from the boiler, and when 
none has been drawn from it for some little time. 

The hygrometric condition of the air is neglected, and its tem- 
perature and its barometric pressure; or, if observations are taken 
of the hygrometer, thermometer and barometer, the corrections 
these instruments would supply are rarely made. Steam-gauge 
pressures indicate different absolute pressures, and different quanti- 
ties of heat, at varying barometric pressures. 

Little attention is usually given to the question : How large a 
proportion of the air in the chimney gases really passes through the 
incandescent fuel on the grates % and how much infiltrates at cracked 
or ill-fitting doors, at cracks in the brick-work, and between the 
brick-work and arch front, or through the brick- work itself ? Lastly, 
it is believed that this is the first serious attempt, outside of the 
technical school or laboratory, to carry out a thorough, continuous 
analysis of flue gases — by far the most important point of attack 
upon the difficult problem of coal combustion. Unless the com- 
position of the escaping gases is known, nothing is known ; this 
accurately ascertained, and their weight and temperature, almost 
everything which it is desirable to know is ascertainable. 

Some of the instruments devised and constructed for these exper- 
iments, and used in carrying them on, will be found of interest. 
Such are the calorimeter, the water-platinum pyrometer, the two- 
fluid anemometer and the incased aneroid barometer. 

This warm-blast apparatus seems to afford a means of securing a 
net saving of 10 to 18 per cent, over the best attainable practice 
with natural chimney draft and with air supplied to the furnace 
at usual external air temperatures ; at least five times as much as 
can be saved by any and all other methods, save the Green Econo- 
mizer, which is an analogous device, only available where large 
quantities of warm water are in constant demand ; and should com- 
mend itself to the attention of all large consumers of coal, as soon 
as the durability of the apparatus is well established by sufficiently 



OBJECTS OF THE EXPEEIMENTS. 3 

protracted use. There are some incidental advantages, growing out 
of the more complete control of the rate of combustion ; and there 
is, it must be said, an offset to these advantages in the more rapid 
deterioration of lire grates, the importance of which can only be 
determined by prolonged experience. 

The expense of these experiments, which grew out of a sugges- 
tion at the end of a pamphlet "On the Combustion of Fuel" * was 
borne by an association of mill owners and manufacturers. Their 
object may be stated as follows : 

1. To ascertain how large a portion of the heat generated by the 
combustion of commercial coals, with the best attainable practice 
by natural chimney draft, escapes through the chimney, serving 
no useful purpose except in producing the draft. 

2. To ascertain what portion of such escaping heat could practi- 
cally be arrested and returned to the furnace in a warm blast, by 
means of an apparatus of admissible size and cost. 

3. To determine the form and dimensions of apparatus sufficiently 
well adapted to this purpose. 

4. To ascertain the cost of driving a blower to supplement the 
loss of chimney draft suffered in consequence of the reduced 
temperature of the iinally-escaping flue gases. 

5. To obtain by observation the data for striking a balance of 
advantages and disadvantages resulting from the use of such appa- 
ratus, as compared with natural draft, under conditions substan- 
tially similar; and 

6. To obtain as much information as such experiments could be 
made to yield upon all questions relating to the economical combus- 
tion of coals and the generation of steam. 

It will be apparent, on reflection, that the problem was far from 
simple, and by no means easy. It would not do to confine the ex- 
periments to a boiler with the warm-blast apparatus, and then to 
institute a comparison with alleged results obtained in ordinary 
practice, since there might easily be found in " ordinary practice " 
defects of care, skill or arrangement, which would make the com- 
parison unduly favorable to the device. Again, the use of a blower, 
or exhaust-fan, by giving control of the draft, would give facil- 
ity for more rapid combustion, and, consequently, for more rapid 
steam generation, which, unless guarded against or duly allowed 
for, might, by increased " priming " — water entrained with the 
steam but unevaporated — have given a deceptive appearance of ad- 

* See Appendices III. and IV. 



4 TRIALS OF A WARM-BLAST APPARATUS. 

vantage arising from a positive loss; a favorite ruse of empirical 
boiler-improvers time out of mind. 

It was therefore thought necessary to lay out a comprehensive 
series of experiments ; first, with a boiler similar in form, dimen- 
sions and setting to all the fifty boilers of the Pacific Mills, in order 
to ascertain just how near to theoretically perfect conditions we 
could bring that boiler, in actual practice, week by week ; and 
secondly, just what proportion of the inevitable loss of heat was 
suffered at the chimney, and what degree of efficiency was attain- 
able. 

This knowledge gained, as a secure basis of comparison, similar 
experiments, modified only so far as necessary to adapt them to the 
modified arrangement of the boiler setting, were carried out with 
the boiler fitted with the warm-blast apparatus : the two sets of ex- 
periments being designated, for distinction, " cold blast " (or Pacific) 
and " warm blast." 

The observations covered the following points : 

1. Coal. — Time of each firing and quantity fired ; quality and 
condition ; temperature ; samples taken at every firing, and analy- 
sis of the daily samples. 

2. Pefuse. — Divided into " cinders," picked out by hand, yield- 
ing by analysis about 41 per cent, of carbon ; partly burned coal, 
about 62 per cent, carbon ; and ashes, of several grades, about 14 
per cent, carbon. Several screens of different degrees of fineness 
were used, and the several grades were weighed, sampled and ana- 
lyzed, for the few first weeks. But a very perfect check upon this 
work (which will be pointed out farther on), enabled us to dispense 
with these laborious and costly analyses of refuse. 

3. Water. — Quantity fed into the boiler ; time and weight noted 
every time a tank was emptied ; height of water level in glass 
water-gauge attached to boiler — temperature and height noted every 
quarter of an hour. 

4. Air.— Quantity, with cold-blast, deduced from the composition 
of the flue gases, determined by continuous analysis, together with 
the tension of these gases, and their temperature : the tension as- 
certained by means of a large aneroid barometer inclosed in an air- 
tight case, communicating through a tube with the flue, and, by a 
three-way cock, with the atmosphere ; and the temperature by means 
of mercurial (chemical) thermometers, inserted in tubes filled with 
sperm oil, set in the flue. With the warm blast, in addition to the 
foregoing, a record was kept of the revolutions of a Root blower 



SUBJECTS INVESTIGATED. 5 

of known measured capacity, and ascertained rate of leakage. The 
hygrometric state of the air was deduced by quarter-hourly 
notes of a hygrometer. The temperature of the external air and 
of the air of the boiler-room was regularly noted, and with the 
warm blast, the temperature on entering the " abstractor," to be 
warmed by the outflowing gases, and again on emerging from the 
abstractor, to enter the ash-pit. 

There was also a hot-air flue for highly heating (at will) a part of 
the air, with provision for introducing it at a " split bridge," with 
dampers to regulate its admission, and provision for observing the 
temperature of such highly heated air. 

5. Gaseous Products of Combustion. — Continuous analysis by 
the gravimetric method, each forenoon's and each afternoon's pro- 
duction by itself, with occasional special examinations of shorter 
periods, to observe the effect of modes of firing, of introducing hot 
air, and other variations from the usual conditions. The gases given 
off during the night from banked fires were also continuously ana- 
lyzed and their volume determined, in the experiments with cold 
blast; but with the warm blast, the dampers were finally made so 
tight that no current could be detected, and the loss — whatever it 
was — could not be estimated. This gravimetric method of gas 
analysis, which is very interesting and not hitherto generally prac- 
ticed, will be fully described in its proper place. 

6. Steam. — Pressure recorded by an Edson pressure-recording 
gauge, and noted every quarter of an hour by a test gauge, known 
to agree with a mercurial column ; supplemented by quarter-hourly 
readings of a signal service (mercurial) barometer; and its qual- 
ity as to saturation, moisture or superheating ascertained. This 
was done with cold blast, in which case the boiler had no super- 
heating surface, by a steam calorimeter, to be hereafter described ; 
and with warm blast, in which case there was ample superheating 
surface and constant superheating in fact, by the thermometer. 

7. Fire. — Temperature in center of incandescent coal, at bridge 
wall, and at the pier, where the gases are about to enter the boiler 
flues, taken by the water-platinum pyrometer. 

8. Flue Gases. — Their temperature on emerging from the 
boiler flues, in smoke-box; on entering the abstractor; on emerg- 
ing from the abstractor, and on passing to the exhaust blower. 

9. Brick-work. — Radiation from its surface ; conduction of heat 
from inside to outside. 

For carrying out these experiments, several new instruments, or 



6 TBIALS OF A WABM-BLAST APPABATUS. 

new forms of old ones, were devised and constructed. The more 
important of these will be found described in the proper place. 

It is obvious that these observations and experiments could not 
all be carried on simultaneously and kept up throughout the whole 
period covered by the tests, without a larger force of assistants 
than it would have been judicious to employ. Nor was this neces- 
sary. Calorimetric experiments on the quality of steam, for 
instance, which are delicate and laborious, demanding the closest 
attention of skillful observers, can be so timed with respect to the 
rate of steam generation and consumption as fairly to represent 
ordinary conditions. Such experiments were, in fact, confined to 
one week, July 11-16, 1881, when fourteen experiments, fully 
detailed in the appropriate place, were made and recorded. 

Pyrometric experiments in the fire, at the bridge wall and at 
the pier, were chiefly directed to ascertaining the temperature of 
new fires, well-kindled fires, new, old, or spent fires, and banked 
fires, with anthracite and with bituminous coal. 

Experiments on the radiation and conduction of brick-work 
were made as time and convenience would permit. 

Valuable information was obtained on the necessity of carefully 
sampling the gaseous products of combustion, which exist in flues 
and chimneys in most heterogeneous mixtures, far from being 
equally diffused ; and on practicable methods of satisfactory sam- 
pling, all of which are fully described. 

The power consumed in driving the suction blower was carefully 
ascertained. Some curious experiments, not devoid of interest, 
were made to ascertain the quantity of solid carbon carried off in 
black smoke with the chimney gases from bituminous coal — a very 
small proportion of the carbon consumed. 

Each one of the tests of evaporation here reported was carried 
on continuously during an entire week. Early on Monday morning, 
the boiler and the water it contained being cooled down nearly to 
the temperature of the boiler room, a wood fire was lighted and 
kept up until the steam gauge showed about 50 pounds pressure 
per square inch, whereupon the fire was drawn, and the furnace 
and ash-pit were cleaned out. A quantity of wood, usually about 
263 pounds, weighed and sampled for analysis,* was then put on 
the fire grate for kindling, and coal was thrown on at the discretion 

* Several analyses of the wood were made, but as these analyses are trouble- 
some, as the quantity of wood used was small, and as dry wood is nearly uniform 
ki composition, the usual ratio, 40 per cent, of coal, was adopted. 



BEGINNING AND ENDING TEIALS. 7 

of the skillful and attentive fireman, and weighed at every firing. 
A platform scale, fitted with a box of plank, having sides and a 
back, but open in front, was kept exclusively for weighing coal. 
500 pounds of coal filled the box conveniently full — the box itself 
being balanced by a counterpoise on the scale beam. The weight 
of a charge and the time of charging being noted, the weight was 
again taken and noted after each firing, and the time of opening 
and closing the fire door was also noted. The successive differ- 
ences were the quantities thrown on the grate at the respective 
firings, and their sums were the total quantities fired during the 
period covered by the notes summed up. 

The notes of each day's firing were plotted, graphically, on sec- 
tion paper, to guard against errors and omissions. 

Near the close of tne day, as early as the demand for steam would 
permit, the fire was "banked," all dampers were closed and so left 
till morning, when the dampers were opened, the fire was cleaned, 
and fresh coal was thrown on. It is, therefore, evident that all the 
fuel consumed during the week has been charged to the boiler, ex- 
cept the wood consumed on each Monday morning in raising steam 
to about fifty pounds pressure. 

The actual pressure at starting the fire and at opening the damp- 
ers in the morning, was observed and recorded, together with the 
height of water in the boiler, this latter being taken from a scale 
attached to the glass water-gauge ; and similar observations were 
noted at stopping, as well as every fifteen minutes of the day — and 
sometimes of the night — and the differences in height of water and 
in pressure of steam, between starting on Monday morning and 
stopping at noon on Saturday, were duly allowed for. A table 
will be found on a subsequent page giving the number of pounds of 
water contained in the boiler at each inch in height of the glass 
water-gauge, from to 10 inches, and for pressures varying by 5 
pounds, from atmospheric pressure to 80 pounds above, with differ- 
ences for convenience of interpolation. 

As to the omission of the quantity of wood consumed in raising 
steam on Monday morning, it is proper to forestall criticism by the 
remark that in no other way could the several trials be made so 
strictly comparable as by starting and stopping in each case, as 
nearly as possible, with steam at the same pressure and with water 
at the same level. The same method was pursued in every case, 
so that the comparison of one ca&j with another is as just as it seems 
possible to make it without continuous uninterrupted firing. 



8 TBIALS OF A WABM-BLAST APPARATUS. 

The anthracite coal was Lackawanna, taken from "pockets" in 
Boston, egg size, very uniform, and of good quality and reasonably 
dry, the analysis showing only 2.78 per cent, of water. 

The bituminous coal was Cumberland, kept under cover, and was 
also of good quality, and contained even less water than the anthra- 
cite. 

Samples about as large as a coffee-bean were taken at each firing 
— averaging about one from ever} 7 tenth lump (of the anthracite), 
each full day's samples filling a compartment three inches cube, in 
a box containing six such compartments; and all the samples of 
each week were pulverized and treated in the usual manner. 

Two independent analyses were made of each week's samples, 
and sometimes, when there appeared to be too much difference, a 
third analysis was made for confirmatiou or correction. A con- 
siderable quantity of each of the pulverized samples, each separately 
bottled and labeled, is preserved for future verification, if desired. 

A summary of the results of coal analysis is subjoined (Table I.), 
the anthracite used with cold blast being the mean of five weeks' 
firing. 

TABLE I. 



CONSTITUENTS OF COAL. 



Carbon . . . 
Hydrogen 

Ash 

Water . . . 
Oxygen . . 
Nitrogen. 
Sulphur. . 



BOILER WITH COLD 
BLAST. 



Anthracite. Bituminous. 



82.43 

1.8G 

10.12 

2.78 



2.81' 



100.00 



81.03 
3.84 
7.19 
.63 
4.49 
2.00 
.82 



100.00 



BOILER WITH WARM 
BLAST. 



Anthracite. Bituminous. 



81.51 
1.89 

11.83 
2.49 



2.28* 



100.00 



81.71 
3.79 
5.75 

1.02 
4.91 
2.00 



100.00 



The two boilers with which experiments were made were pre- 
cisely alike, and were substantially like all the boilers in use at the 
Pacific Mills, about fifty in number, some of which are a little less 
in length. They are of the class known as externally tired, return 
tubular boilers. The cylindrical shell, of fiange iron 0.375 inches 
thick, is 60 inches in diameter outside of the small courses, double- 
riveted in the longitudinal seams, and 21 feet in extreme length, 

* The Oxygen, Nitrogen and Sulphur not separated in the anthracite. 



DESCRIPTION OF BOILERS. 9 

including the smoke -box cover ; the smoke-box at the front end 
being 1 foot long, and the flues 20 feet. These are 3.5 inches in 
diameter outside, lap-welded iron tubes, set in squares and in 
straight rows both horizontally and vertically, 4.5 inches between 
centers, and therefore with 1 inch clear space between them. 

They are arranged in 7 horizontal rows ; 4 rows of 11 tubes each, 
one of 9, one of 7, and one of 5, making 65 tubes in all. The middle 
tube of the row next to the upper row, is in the center of the shell, 
which leaves at the bottom a space of 5.37 inches between the 
lower side of the flues and the inner side of the small courses, 
4.87 inches between the flues and the rivet-heads, and at the near- 
est, 3.09 inches, radially, between the flues and the smaller courses, 
and 2.59 inches between the nearest tubes and the rivet-heads. 
The provision for water circulation is therefore sufficient, and is 
further aided by setting the smoke-box entirely forward of the 
arch front, so that a length of 12 inches of the water space at the 
front end, immediately back of the smoke-box, is embraced in the 
brick-work, and shielded from the direct action of the fire, which, it 
is believed, produces a downward current at that point, to supply 
the rapid evaporation directly over the fire-grates. These are 5 
feet 2 inches long from the fire-brick lining of the arch front to 
the bridge wall. 

The fire-grates of the original " Pacific " boiler, with which the 
cold-blast experiments were made, were 5 feet wide between the 
side walls; those of the new boiler, with hot-blast apparatus, 5 feet 
4 inches wide. The side walls of the Pacific boiler are offset 
above the grates, until at the level of the bridge wall, they are 5 
feet 6 inches apart, at which point they are 24 inches thick ; and 
are closed over against the boiler at the middle of its height, where 
the space is 3 inches to the smaller courses, 2.62 inches to the 
larger courses, and 2.12 inches to the rivet-heads. The brick-work 
closing the space between the side walls and the boiler, is 9 inches 
in depth, and above it the right-hand side wall is carried up 3 
inches above the top of the boiler, where the covering bars are 
laid on. The left-hand side is occupied by a horizontal brick flue, 
conveying the gases of combustion, received from the smoke-box 
through a plate-iron smoke bonnet, to the rear of the boiler setting, 
where a vertical brick flue, 16 X 36 inches, conducts them down 
below the floor of the boiler-house, to enter the side of an under- 
ground brick flue extending along in the rear of the boilers to the 
chimney, located just outside of the boiler-house, as seen in Fig. 1. 



10 TRIALS OF A WARM-BLAST APPARATUS. 

The covering over the boiler is as follows: suitable east-iron 
bars of J_ section are laid about 3 feet apart, across the boiler, 
supported by the side wall of the boiler setting on one side, and 
by the wall of the flue on the other side. On the flanges of these 
bars were placed, at intervals of a brick's length — 8 inches — smaller 
bars, of similar section, on the flanges of which bricks were placed ; 
and on the covering so made two courses of brick were laid in 
mortar. The space between this covering and the boiler is left 
vacant. Suitable openings are left for access to the man-hole 
cover, safety-valve seat, and feed-water inlet. The side and end 
walls, reduced to 12 inches in thickness, are carried up two or 
three courses higher than the covering over the boiler, in the form 
of a low parapet. 

The boiler is supported at the front end by the arch front, at the 
rear end by a massive pier of flre-brick, and on the side wall by 
strong lugs, two on each side, riveted to the boiler. 

Feed water is supplied to the boiler at the top, near the rear end, 
through a nozzle provided for the purpose, through a pipe carried 
down to and into the water, and around the flues nearly to the 
bottom, to enable the feed water to acquire nearly the temperature 
of the water in the boiler before its discharge from the pipe. 

All the experiments with cold blast, and with natural chimney 
draft, were made with this Pacific boiler and boiler setting, as above 
described. Subsequently, the warm-blast apparatus was placed on 
top of this boiler; but without any alteration of the boiler-setting, 
except to discontinue the use of the horizontal flue on top and the 
vertical flue in the rear ; and to make flues on each side for the 
warm blast, from the front end of the abstractors to the ash-pit. 
It will be seen from this description that this boiler has no super- 
heating surface, unless the two or three square feet above the water 
level in the smoke-box be so considered, and as the gases here are 
but a few degrees warmer than the steam in the boiler, this is too 
trivial to produce a sensible effect. 

The top of the fire-grates is 20 inches below the bottom of the 
boiler ; the top of the bridge wall, 12 inches above the grates, and 
the pavement back of the bridge wall, 22 inches below the top of 
the bridge wall, and 30 inches below the boiler. The whole — fur- 
nace and combustion chamber — is lined with fire-brick, all headers 
in the furnace ; and the rear wall is brought over by offsets, nearly 
to contact with the end of the boiler, above the flues, large tile, 
18 inches long, 12 inches wide, and 3 inches thick, being freely 



BOILEK-HOUSE. 



11 




12 TRIALS OF A WARM-BLAST APPARATUS. 



REFERENCES TO GROUND PLAN OF BOILER-HOUSE. 

A, A, Water tank on platform scales. 

B, Water meter. 

C, Water pipes and valves for filling tanks. 

D, Platform scales for weighing coal. 

E, Calorimeter on its platform scale. 

F, Screen to protect calorimeter from radiant heat 

G, Edson pressure recording gauge. 
H, Test steam gauge. 

I, Steam pipe to supply injector. 

K, K, Pipe for direct water supply ; not used during these experiments. 

L, Main steam pipe : wrapped with felt. 

M, Root blower, for exhausting gases. 

N, Steam engine to drive blower. 

P, Man -hole of boiler. 

Q, Condenser for ascertaining the quantity of heat rejected by the steam 
engine. 

R, R, R, R, Cold-air boxes leading to abstractors. 

S, S, Abstractors of boiler No. 1. 

T, Steam pipe to supply steam engine N. 

U, U, Small doors for inserting heat-carriers of pyrometer, at bridge wall and 
pier. 

V, Shelf for pyrometer, at pier. 

W, W r ater pipe from injector to boiler. 

X, Chimney. 

Y, Coal shed. 

Z, Horizontal flue on top of boiler with cold blast : subsequently removed, 
when the second form of abstractor was applied to this boiler, converting it into 
warm-blast boiler No. 2. 



SUPEBHEATING SUEFACE. — SHUT OFT. 13 

used to give strength and stability to this overhanging wall ; and 
for the same purpose the rear wall was made 3 feet 4 inches thick. 

The boiler to be designated boiler No. 1, warm blast, was pre- 
cisely similar to the " Pacific " boiler described above, but its set- 
ting was in some respects quite different. 

The side walls are 33 inches thick, 9 inches being of fire-brick 
and 24 inches of red brick. This gives room for descending flues 
on each side, 8 inches in thickness, from the abstractors to the ash- 
pit, with 9 inches of fire-brick between them and the fire, and 16 
inches of red brick outside. These walls are placed 5 feet 6 inches 
apart, and are plumb all the way up to 1 inch above the axis of the 
boiler, except a slight contraction of the space between them, of 
1 inch on each side, at the fire grates, which are 5 feet 4 inches 
wide. From the top of these walls, a semicircular arch is sprung 
over the boiler, leaving a clear space between it and the smaller 
courses of the boiler of 3 inches at the sides, and 4 inches at the 
top, into which the hot gases could freely ascend, although no cur- 
rent could pass through. The temperature found in this space at 
the top — 700° to 900° F. — gave at all times a slight degree of 
superheating, and care was taken to carry the water pretty high in 
the boiler, to avoid danger of injury to the plates. 

At the close of the experiments with this boiler, before turning 
it over for regular use, large fire-brick tile — 18 x 12 x 3 inches — 
were inserted, one by one, the whole length of the boiler on both 
sides, just below the arch, closing up the space between the side 
walls and the boiler, so that there was thereafter no superheating 
surface in this boiler. The reason for shutting off" the superheating 
surface, when no longer required for experimental purposes, was 
to guard against overheating the plates. 

The space between the rear end of this boiler and the rear wall 
is closed, or covered, above the flues, by a transverse arch of 5 feet 
span, 12 inches versed sine and 42 inches radius, resting on corbels 
brought out 3 inches on each side from the face of the side walls, 
at about the level of the axis of the boiler. This arch, composed, 
in fact, of a series of superimposed arches, one fire-brick (4.5 
inches) in depth, w r as carried up even with the intrados of the arch 
over the boiler, which was continued on over it, to break the joint 
and to make the brick-w r ork continuous ; but was not built up close 
against the end of the boiler, a space of 0.75 inch being left for 
difference of expansion between the boiler and the brick-work. 

One reason for arching over the boiler in the manner described, 



14 



TRIALS OF A WARM-BLAST APPARATUS. 



was to obtain a secure foundation for the abstractors. These were 
placed on top, one at each side (Fig. 2), leaving a space of 3 feet 
in width between them, for access to the man-hole, safety valve and 
other attachments on top of the boiler. Side walls 8 inches thick, 
32 inches apart, the face of each outside wall flush with the face 
of the side wall of the boiler setting, were covered over (after the 
tubes of the abstractor were put in), by supporting ± bars 8 inches 
apart, and by 3 courses of brick resting on these bars. The flues for 
conveying the gases of combustion through the abstractors from 




Fig. 2. 

CROSS SECTION OF WARM-BLAST BOILER NO. 1, THROUGH FURNACE. 



the smoke-bonnet to the blower at the rear of the boiler, are 240 
in number — 120 in each abstractor — of ordinary lap-welded tubes, 
2 inches in diameter outside and 20 feet long, set by expanding 
their ends in cast-iron flue sheets provided with suitable flanges for 
fixing them securely in the brick-work. These 2-inch smoke-flues 
are set 3 inches apart, between centers, in 12 horizontal rows, 10 
tubes in each row, in each abstractor, in equilateral triangles ; 
and incased, each one in a 3-ineh tube of thin iron, locked spirally, 
leaving between the smoke-flue and the incasing tube an annular 
space a little less than 0.5 inch in width radially, with pegs pro- 
jecting from the inner flue to keep each tube and its casing in a 



WARM-BLAST APPARATUS NO. 1. 15 

concentric position. The 3-inch tubes were bedded in mortar, and 
rested against each other at their lines of contact. 

The 3-inch tubes were only 18 feet long— 2 feet less than the 
2-inch smoke-flues. As the air to pass through the 3-inch tubes, in 
the annular space between them and the 2-inch smoke-flues, was to 
be received at the rear end, at the top, and discharged at the front 
end at the bottom, the rear ends of the upper rows and the front 
ends of the lower rows of incasing tubes, were set 21 inches from 
the respective flue sheets ; and the front ends of the upper rows, 
and the rear ends of the lower rows of these same tubes were set 
3 inches from the flue sheets ; and the ends of all intermediate 
rows at proportionate distances, in order to facilitate the admission 
and discharge of air. A cold-air box of thin plate iron, provided 
with an air-tight damper at its outer end, and branching equally to 
the two abstractors, supplies air from without the boiler-house at its 
rear end, and the descending flues in the brick-work already men- 
tioned conduct the warm air from the abstractors to the ash-pit, 
through arches in the side walls, below the fire grates (Fig. 3). 

The gases of combustion are conveyed from the smoke-box to 
the abstractors at the front end, by a branching smoke-bonnet of 
ample area (less would be better, causing less radiation), and at 
the rear they are drawn together again through converging flues to 
a single descending brick flue leading to the exhausting blower, 
which discharges directly into the under-ground brick flue leading 
to the chimney. 

Tightly closing dampers are placed in the descending smoke-flue 
at the rear, and in the descending air-flues at the front, and regu- 
lating dampers, like throttle valves, are also placed in these latter. 
There is also a damper below the exhausting blower, and in line 
with the descending smoke-flue, which serves, when open, as a " by- 
pass " to permit the gases to flow to the chimney by natural draft 
when the blower is not in motion. 

Small iron doors, 6 inches square, with isinglass panels, were set 
in the right-hand side wall, one opposite the bridge wall, the other 
opposite the pier at the rear end of the boiler, for the insertion and 
removal of the heat-carriers (platinum balls, in black-lead crucibles), 
of the platinum-water pyrometers. 

In addition to the necessary and proper arrangements heretofore 
described, there were certain contrivances, destitute alike of merit 
and novelty, introduced for reasons which it is not necessary to ex- 
plain. 



16 



TEIALS OF A WARM-BLAST APPARATUS. 




FLUES FOR HEATING AIR: SPLIT BRIDGE. 17 

One of these was a set of perforations in the side walls of the 
furnace, for the admission of warm air drawn from the descending 
air flues, above the incandescent fuel. Four tiles of fire clay, each 
18 inches long, 12 inches wide, and 4 inches thick, each one pierced 
with 187 holes f-inch diameter in front and f-inch in rear, were 
set, two on each side, end to end, about in the middle of the length 
of the furnace, and exactly opposite the descending warm-air fines, 
with their lower edges 12 inches above the fire grates. Sliding 
u gridiron " dampers, with handles extending out through the arch 
front, were set behind these perforated tiles and a few inches from 
them; and great care was taken to make these dampers, w r hen 
closed, as tight as possible, to reduce to a minimum the harm which 
the admission of air above the fuel could not fail to do. Careful 
and repeated experiments and observations proved that these 
dampers could never be opened without checking the draft 
through the fuel, and lowering the temperature of the fire; and it 
is not impossible that a very little leakage through the closed 
dampers may have lowered in a slight degree the efficiency of the 
boilers. 

Another of theae venerable contrivances, which is likely to be 
tried over and over again every few years till steam engines are no 
more, was a circuitous flue for heating air, or " superheating " it 
(whatever superheating may be supposed to mean when applied to 
a permanent gas), for admission to the combustion chamber through 
a channel and orifices in the bridge wall, technically known as a 
" split bridge." 

This superheating flue was built entirely within the combustion 
chamber, back of the bridge wall, extending along the face of the 
side and rear walls, and was constructed in the following man- 
ner: 

A wall of fire-brick, 3 inches thick, placed on their edges, three 
bricks high, was laid on the pavement back of the bridge wall, par- 
allel to the side wall and to the rear end wall, at a distance of 4 inches 
from these walls. A course of headers 9 inches long was then 
laid, covering the flue, and bonded 2 inches into the walls, forming 
a flue 4 inches wide and 13.5 inches high, around the sides and 
rear of the combustion chamber. On top of this flue, another flue 
exactly similar was placed, both having their angles at the rear 
truncated a little, to diminish the resistance. The uppermost of 
these two flues was connected, just behind the bridge wall, with the 
vertical air flue on that side, through which warm air descended 



18 TRIALS OF A WARM-BLAST APPARATUS. 

from the abstractor to the ash-pit, admission of air to the super- 
heating flue being regulated by a damper hinged at its lower edge, 
in such a manner that when open it extended obliquely into the 
vertical fine, so as to arrest a portion of the descending warm air, 
and to direct it into the superheating flue. At the opposite end 
of the bridge wall there was an opening through the horizontal 
partition between the upper and lower superheating flues, so that 
the air might descend to the lower flue and return to a point di- 
rectly beneath the place where it entered the upper flue. Here 
was an opening into the split bridge ; so that after twice making 
the circuit of the side and rear walls, the air, presumably consid- 
erably heated, might pass into the channel in the split bridge, 
and through small openings in its rear, to mingle with the hot 
gases flowing over the crest of the bridge wall. Subsequently, an 
additional wall of fire-brick was laid behind the bridge wall, to 
turn the superheated air upward. 

No good was ever found to result from this system of flues; in- 
deed, it is doubtful if any considerable quantity of air ever passed 
through the flues at all, although some must have flowed in when 
the dampers were opened, since the resistance of the open flue, 
circuitous as it was, could hardly have been so great as that of the 
coal on the Are grates. 

But since the only combustible substance present in the smoke, 
carbon monoxide (CO), never, in the day-time, exceeded half of 
one per cent., and rarely exceeded half that small quantity when 
the dampers were open, for six weeks together, it was impossible 
that combustion could be sensibly promoted by the admission, at 
the rear of the bridge wall, of a further supply of air, however 
much " superheated." 

A certain very slight advantage resulted, indirectly, from the in- 
terposition of 3 inches more fire-brick, to check radiation where it 
was most active ; but this device and that of perforated tile pre- 
viously described are here given much in detail in order to show 
that their uselessness did not result from imperfect design, inade- 
quate extent, or defective construction ; but simply from the futil- 
ity of attempting to burn over again the products of combustion 
already substantially complete, by the admission of air, however 
heated, where air, at the temperature of the hot gases themselves, is 
already in excess by 100 per cent., and most intimately inter- 
mixed. 

It was assumed at the outset that cast-iron grates could not with- 






WATER GRATES. — WILLIAMS GRATES. 19 

stand the heat resulting from the introduction of warm blast, and 
a water grate was provided of a construction supposed to be safe 
aud durable, although costly, consisting of a top and bottom plate, 
3 inches apart, united at their edges by a hoop, and having a suffi- 
cient number of short tubes set through them for the admission of 
air. Provision was made for circulation, by a diaphragm in the 
middle of its width, connecting it with the water space below the 
flues, and dividing the furnace longitudinally into two equal parts. 
After repeated trials, this grate leaked so badly that it was dis- 
carded, and the ordinary long grates of the Pacific Mills were 
tried. These were cast two bars together, 5 feet 2 inches long, 0.75 
inch thick on top, 0.50 inch at 0.62 below the top, and 0.31 
inch at the lower edge ; and 5.5 inches deep in the middle. The 
spaces between grate bars were 0.5 inch, so that the openings, 
without deduction for obstructions at the ends and at the two in- 
termediate side supports, were equal to 40 per cent, of the whole 
grate area; and allowance made for all obstructions, the clear space 
was equal to 34 per cent. These grates, supported at their ends only, 
were not destroyed by three weeks' use with warm blast ; but they 
gave evidence of injury in places, which made it plain that they 
might suddenly melt down at any time, and other grates, admitting 
of more support from below, were tried with entire success. These 
were the Williams rocking grates, supported on bearers in sections 
only about 15 inches long, and provided with a means of clearing 
them by shaking from below, through the ash-pit door. In firing 
with stationary grates, it was found necessary to keep the fire doors 
— one at least — open one hour out of ten hours' firing, to clean the fire 
and draw the clinker. This invariably lowered the temperature all 
the way from furnace to smoke-box, diminished the draft through 
the coal on the grates, produced an increased quantity of carbon 
monoxide (CO), in the chimney gases, and reduced the efficiency 
of the boiler. With the rocking grates, the time of slicing and clean- 
ing the fire was reduced to ten minutes once a day, at 5.30 p. m. 
The short, sectional grate bars next to the bridge wall suffered 
pretty rapid deterioration, and in a less degree those at the front and 
sides. Some form of grate still better may be found ; but it seems 
probable that the life of any grates, whatever their form, will be 
less with warm blast than with air taken in at the external tempera- 
ture — unless, indeed, a water grate can be used. What the excess 
of cost for grates may be, to offset the gain by warm blast, can 
only be determined by experience of some duration. 



20 TKIALS OF A WAKM BLAST APPAEATUS. 

After the conclusion of the experiments with Warm-Blast Boiler 
"No. 1 (weeks G & H of Record, ending February 4 and 11, 
1882), the original Pacific Boiler was converted into Warm-Blast 
Boiler No. 2, by the simple addition of the abstractors and the 
air passages and smoke flues necessary to convey the gases through 
the abstractors to the exhaust blower, and the air in the opposite 
direction from without the boiler-house to the ash-pit. 

No alteration was made in the boiler ; and none in the brick- 
work, otherwise than to build the two vertical flues near the front 
end, to conduct the warm blast down to the ash-pit, and into it by 
arches in the side walls below the lire grates. 

These vertical flues occupied, in part, a space of 8 inches origi- 
nally left between the side walls, and, on the left the wall of the 
boiler-house ; on the right the side wall of Warm-Blast Boiler 
No. 1. 

The mode of construction first adopted in Warm-Blast Boiler 
No. 1, has been fully described. 

The principles involved in that construction were : 

1. The division of the air passages into 2tL0 annular channels of 
uniform cross-section between (a) lap-welded smoke flues 2 inches 
in diameter outside, and (b) spiral-locked sheet-iron tubes 3 inches 
in diameter outside, in order to give uniform velocity to the air, 
and equal exposure of the air to the warm surfaces. 

2. The great addition to the warm surface made by these exter- 
nal tubes, which would be warmed by radiation from the 2inchflue? 
to almost uniform temperature with them, since air is not sensibly 
affected by radiant heat. There would therefore be two metallic 
surfaces in contact with the thin annular stream of air, the inner 
one 6 inches, the outer 9 inches in circumference, amounting to 
300 square feet for each foot in length, and for the whole 20 feet 
to 6,000 square feet. 

3. The skin friction of the 3-inch tube being greater than that 
of the 2-inch flue, not alone on account of its 50 per cent, greater 
area, but also on account of the slightly projecting spiral line of 
joint within, corresponding with the prominent spiral interlocked 
ridge on the outside, the air must acquire a rolling motion from 
within outward best calculated to bring all parts of the inflowing 
air into frequent contact with the warm surfaces, and to uniform 
temperature with those surfaces. 

Much apprehension was felt that the smoke might pass in largest 
volume through the lower courses of 2-inch flues — those first en- 



WAEM-BLAST APPAEATUS NO. 2. 



21 




fe fa 
o o 



22 



TBIALS OF A WAEM-BLAST APPARATUS. 



countered on leaving the smoke-box ; and that the air, on the other 
hand, entering at the top, might flow in greatest volume through 
the upper annular passages, and that so the effect might be dimin- 
ished. But extensive and patient probing with the water-platinum 
pyrometer — the platinum ball being held in the tongs to be de- 
scribed — proved that this apprehension was unfounded — that both 
air and smoke were at nearly uniform temperature at top and bot- 
tom of every cross section. 

Yet the quantity of heat transferred from the escaping gases to 
the inflowing air did not answer expectations based on theoretical 




Fig. 5. 
cross-section of waem-blast boilett no. 1, at pier 
abstractors of no. 2. 



BUT SHOWING THE 



considerations. The gases passed off at a temperature about 160° 
F. above that of the external air, carrying a large quantity of heat 
to waste. The obstruction sure to arise in time from accumula- 
tions of dust in the annular passages, was not lost sight of. The 
cost, too, of the double pipes, was very considerable. It was there- 
fore decided, after due consideration, to adopt a new mode of con- 
struction. 

A piece of 2-inch spiral-locked tube, 4 feet long, with brass fer- 
rules soldered into its ends, having been put to severe tests and 
found air-tight, pipes of that description were adopted for the 



WAEM-BLAST APPARATUS NO. 2. 23 

smoke flues, at a saving of nearly one-half ; and the 3-inch tnbes 
were omitted, and replaced by deflectois, arranged as shown in Figs. 
4 and 5. The 2-inch flues were made 18 feet long, of sheet steel, 
No. 26 American wire gauge (.018 inch thick), each tube formed of 
a single strip 35 feet 6 inches long and 3.5 inches wide. A ring 
or ferrule of copper, equal in thickness to the ridge formed by the 
locked joint (about .054 inch), with its ends cut to the obliquity of 
the spiral joint, so as to fit closely to it on both sides, made an outer 
surface at each end smooth and cylindrical, for expansion into suit- 
able holes in the flue sheets ; and internal thimbles of lap-welded 
pipe gave the degree of firmness necessary to hold the expansion.* 
Partitions of sheet iron, having holes for the 2-inch spiral flues 
corresponding in position with the holes in the flue sheets, were 
put into the brick chambers of the abstractors at intervals of about 
a foot ; half of them closed at the top, and extending down to with- 
in 3 rows of flues of the bottom of the chamber, and the other half 
closed at the bottom, and extending up to within 3 rows of the 
top. Air entering at the top must descend across and among the 
2-inch flues, which have spaces of 1 inch between them, pass under 
the first partitions, or " deflectors," then rise in the same manner 
across and among the flues to pass over the second deflectors, and 
so on, until on flowing over the last deflectors, it passes down 
through the vertical brick flues to the ash-pit. 

The deflectors are plain rectangular pieces of sheet iron, No. 18 
w. g., set with their side and top (or bottom) edges about 1 inch in 
the brick-work. The holes are punched, and they cost but a trifle 
in comparison with the 3-inch spiral air tubes. They also support 
the flues at every foot of their length, and they allow dust to collect 
to any probable extent in the corners at the bottom of the brick 
chambers without causing inconvenience. The deflectors, so far 
as they go, supply an additional surface warmed by conduction and 
radiation to impart heat to the air by contact ; and the impact 
of the air in flowing transversely across the flues, although acting 
in each direction only on about one-half the circumference of each 
flue, may yet be counted on to give something of that increased 
effect due to impact of air upon warm surfaces which was first 
pointed out by Leslie. 

For protection against loss by radiation, brick walls and brick 
covering were used as before ; but in order to guard against cracks, 

* A better method has since been dev'sed bj Mr. F. H. Prentiss, by means of 
external and internal malleable iron rings. 



24 TRIALS OF A WARM-BLAST APPARATUS. 

and to cut off leakage, the whole exterior of the brick-work of these 
abstractors was incased in thin galvanized sheet iron, locked and 
soldered. 

The covering of the Pacific boiler, described previously, not 
being strong enough to bear the weight of the abstractors, bars of 
old rails, equal in length to the width of the boiler setting of warm- 
blast No. 1 (11 feet), were placed across at intervals of 2 feet, resting 
on the side walls, and projecting a few inches beyond them. Pieces 
of J-inch plate iron laid from bar to bar on their lower flanges 
supported the brick-work. After leveling up to the top of the 
bars, the sheet iron for the bottom of the casing was laid on, a 
hearth of three courses of brick was laid, the side walls were carried 
up, and, after the tubes and deflectors were all in proper place, the 
covering was put on, and the casing of sheet iron completed. A 
brick flue brought together the two streams of gases from the two 
abstractors, and conducted the united stream to the exhaust blower. 

The results obtained with this apparatus (week I, ending May 
20, 1882), were decidedly better than were obtained with the appa- 
ratus first tried. "With higher temperature of external air, and a 
smaller quantity of air per pound of coal, the final temperature of 
escaping gases was reduced 20 degrees lower. Part of this gain 
may have been due to the manner in which the abstractors are 
supported, on bars, out of contact with the brick-work (which in 
the other case was very hot on account of the superheating arrange- 
ment), so that less heat was imparted by conduction to the abstract- 
ors, to be in part carried off by the smoke. But a part — probably 
the greater part — was due to the greater efficiency of surface im- 
pinged upon by air in motion, over similar surfaces along which 
air flows smoothly, without impact. Something may be due to 
the reduced thickness of the metal, but Peclet's formulae do not 
lead us to expect a sensible effect from this cause. 

The question of durability remains to be settled, but there is 
now reason, after nearly three years' use, to look for a favorable 
result. Both the air and the smoke are at a temperature so far 
above their dew-point — unless, indeed, the boiler leaks badly — that 
no moisture can be deposited on the flues, either within or with- 
out; and there is little danger to be apprehended from sulphur, 
which in the form of sulphurous acid (S0 2 ), is not actively corrosive, 
and of S0 3 (which condensed with water becomes H 2 S0 4 , or 
sulphuric acid), there is never much and seldom any. The an- 
thracites contain but very little sulphur, and the Cumberland 



LEAKAGE OF AIK THEOUGH BRICK-WORK. 25 

bituminous coals only about 0.8 per cent. Pictou coal, it is true, 
sometimes contains sulphur, in the form of iron pyrites, in visibly 
large quantities. 

The cost of the single tubes with deflectors is much less than 
that of the other form, with double tubes : — First, because the spi- 
ral steel tubes cost but little more than half as much as the lap- 
welded tubes of the same size ; second, because they were reduced 
from 23 feet in length to 18 feet, yet seemed to be even more effi- 
cient ; and third, because the deflectors cost much less than the 
3-inch tubes which they replaced. As to the sheet-iron casing 
outside of the brick chamber, that was no less desirable with the 
first form than with the second. 

It is probable that the quantity of air per pound of coal consumed 
was reduced by this air-tight casing, since much air infiltrates 
through brick-work. The extent of this infiltration is surprising. 
So great is it that the flame of a match is drawn to and into the 
interstices of an 8-inch brick wall — not alone at fine visible cracks, 
but at mortar joints apparently sound. 

To cut off this harmful infiltration of air, the outside of the 
smoke-flues in the rear was coated with desiccated tar and shingled 
over with tarred cotton cloth. It might be worth while to leave 
off the outer 8 inches of brick-work of the boiler setting, all around, 
until the inner portion was complete, and then to cover the whole 
surface, sides, ends and top (and preferably the bottom also, to 
keep down moisture), with galvanized sheet iron, locked and sol- 
dered. At the arch front, where very pernicious leakage of air is 
too common, a tight joint could be made by means of a strip of 
sheet iron riveted to the back side of the arch front all around, to 
which the casing could be locked and soldered. If, now, the cas- 
ing were covered with an inch of hair felt, and around and over all 
8 inches of brick-work were laid, secured with binders, as usual, or 
more completely, an appreciable saving of heat would result, per- 
haps exceeding one per cent. An air space is sometimes left in 
the brick-work, for the purpose of reducing radiation. Breaking 
the continuity of the brick-work certainly impedes the outflow 
of heat, by interrupting conduction, and interposing the slower 
processes of radiation and absorption; hut an air space as an 
interceptor of radiant heat is futile. Hardly any substance in 
nature is less useful for this purpose than air, which when dry 
is absolutely diathermanous. It answers well to build the walls 
of three successive, independent S-inch walls, close together, but 



26 TRIALS OF A WARM BLAST APPARATUS. 

not bonded, and free from mortar at their surfaces of contact. 
Conduction is thereby sensibly interrupted, some freedom is left 
for unequal expansion, the binders tie all firmly together, and cracks 
will be less numerous, less continuous, and less disastrous. But 
all cracks, large and small, should be sedulously stopped up. Yery 
large cracks will often be found between the arch front and the 
brick-work. These should be stopped with putty. Smoke-box 
covers and doors, fire doors and ash-pit doors should be carefully 
fitted, and smoke-box doors and covers, which usually require to be 
opened but once a week, should be packed or puttied. Fire doors 
should be made with a groove all around them, to receive a pack- 
ing of asbestos, and should have some provision for pressing them 
firmly against their seats on the arch front. However well fitted at 
first, or when cold, the heat warps them so that they often admit 
sufficient air to impair the draft w r here alone draft is useful — 
through the fuel on the fire grates. For the same reason, the fire 
door should be left open as little as possible. If the grates are 
stationary, it will be necessary, with combustion as rapid as 
12 pounds of coal per square foot of fire-grate area per hour 
(counting all the time the draft is open), to clean the fire and 
draw out clinker as much as six times in ten hours, occupying ten 
minutes each time, equal to one hour in ten — a serious loss, which 
may be reduced five sixths by the use of rocking grates, operated 
through the ash-pit door. But let no grate-vender quote me as 
authority for the stereotyped saving of u 30 percent, of ' the coal.' " 
I believe that an appreciable saving may be made by the use of 
good rocking grates, perhaps two per cent. In the aggregate, these 
small savings become important ; but aside from the one conspic- 
uous saving by returning to the furnace, in a warm blast, a part of 
the heat of the gases of combustion after they leave the smoke-box, 
in some such manner as that herein described, or by its substantial 
equivalent the Green Economizer, no gain of so much as iive per 
cent, over reasonably good ordinary practice can be so much as 
fairly hoped for. 



WATER-PLATINUM PYROMETER. 



27 



II. 



Taking up now a second division of the subject, a description 
will be given of the instruments and apparatus for physical obser- 
vation. 

1. The Pyrometer. — The inner cell, or true containing vessel 
of this instrument, is 4.25 inches in diameter, and of equal height 
on the side, with a bottom in the form of the segment of a spher- 
ical surface of 4.25 inches radius, all of sheet brass 0.01 inch thick, 
nickel plated and polished outside and inside (Fig. 6). The out- 
side case is 8 inches in diameter and 8.5 inches deep, of 16 oz. 




Fig. 6. 
water-platinum pykometer. 



copper, nickel plated and polished on the inside but plain outside. 
There are two handles — on opposite sides — for convenience of 
rapid manipulation. The top, which is depressed conically like a 
hopper, is of the same copper as the sides and bottom, and is ter- 
minated at its outer edge with a strong wire, forming a lip all 
around for convenience of pouring. The central cell is connected 
with the outer case, only by three rings of hard rubber, each 0.25 
inch thick ; the middle ring completely insulating the cell from its 
continuation upward to the hopper-shaped top, by interposing its 
thickness between the flanges of these two parts. The joints 
formed by contact of these flanges with the hard rubber ring, which 



28 TEIALS OF A WAEM-BLAST APPARATUS. 

would be likely to leak water into the spaces filled with eiderdown, 
were made tight by a coating of asphaltum varnish. 

The lower hard rubber ring is, in fact, made up of three concen- 
tric rings, each one supporting the flange of a partition. These 
partitions are complete cups — sides and bottom — of sheet brass 0.01 
inch thick, and, together with an additional spherical segment at 
the bottom, next to the outer case, are nickel plated and polished out- 
side and inside. They divide the space between cell and case into 
three compartments, each about 0.625 inch in thickness, all filled as 
are all spaces everywhere, with eider down. All the four plates of 
the cover are of sheet brass, 0.01. inch thick, nickel plated and 
polished on both sides ; and all are insulated from each other and 
from the vessel by a hard rubber ring, which forms the outer rim 
of the cover, and by a tube of hard rubber with a knob and shoulder 
above and a screw-thread at its lower end, by which the upper and 
lower plates are firmly held together, while the knob serves for 
lifting the cover. 

Through this tube passes the hollow stem of the agitator, the 
upper part of it formed of hard rubber, terminated at top by a knob, 
with a taper hole for a cork, through which a thermometer passes 
down nearly to the bottom of the stem, the lower part of which is 
of brass tube. The agitator conforms to the spherical shape of the 
bottom of the cell, but does not touch it by about 0.25 inch ; and 
has a rim turned up 0.25 inch all around. This agitator and the 
brass portion of its stem are freely perforated with holes 0.2 to 0.4 
inch diameter, and nickel plated and polished. The spherical 
form of the agitator gives a radial direction to the streams of water 
passing through its holes when it is raised and lowered, so that 
very little motion up and down — not enough to lift the hard rubber 
stem out of its hard rubber incasing tube — suffices to mix the water 
perfectly. 

A slight modification, to the form of a propeller, would enable 
it to give equally good mixing by rotatory motion, as strongly 
recommended by Berthelot, and avoid alternate withdrawal and 
re-immersion of any part of the stem. 

Very careful and quite satisfactory determinations were made of 
the calorific value of the metals directly affected by the tempera- 
ture of the contained water ; and just sufficient water was weighed 
in, to amount, with the calorimetric value of the instrument, to 
two pounds of cold water. 

This determination was in its general nature similar to the de- 



TESTS OF PYKOMETEB. 29 

termination of the heat capacity of the calorimeter for testing the 
quality of steam, fully described elsewhere ; but as this instrument 
was designed to hold only about a quart of water, the method 
followed was much simpler, and susceptible of greater accuracy. 

A tin dipper of about two quarts capacity was used to hold the 
hot water, which was poured directly into the pyrometer as quickly 
as possible, whereupon the cover was shut down and the agitator 
was put in motion. The examples given in the case of the steam- 
calorimeter will serve as a type of the experiments with the pyrom- 
eter; but in this latter case a special correction was demanded. 
The cooling of the hot water was augmented by pouring, in con- 
sequence of the exposure to the air of a large surface of water in a 
thin sheet. The effect of this exposure was ascertained in the 
following manner: The instrument was placed in a bath of tepid 
water, so as to bring the temperature of all the materials compos- 
ing it exactly to the temperature of the water to be poured in. 
Thus, whatever diminution of temperature the latter might suffer, 
must be entirely due to the loss of heat by pouring. Four experi- 
ments, carefully made, gave the following results : Loss of tem- 
perature by pouring, at 170° F., 0.81°, 0.86°, 1.00°, and 1.07° ; mean, 
0.935° F. 

The following six values of the calorific capacity of the metals of 
the pyrometer, which share directly the temperatures of the in- 
closed water, including also the thermometer used with the instru- 
ment, were found by experiment : 0.1048, 0.1052, 0.1077, 0.1008, 
01028, 0.1104. 

Mean, 0.1053, = lbs. 1 oz. 11 drms. 

Add water, 1.8947, = 1 14 5 



2.0000, = 200 

This mean was the value used. The instrument being put on 
delicate coin scales and counterbalanced, weights equal to 1.8947 
pounds avoirdupois, = 1 lb. 14 oz. 5 drms., were added to the coun- 
terbalancing weights, and cold water was poured in until the scales 
again balanced. 

The vessel and its contents were then just equal in heat capacity, 
while the temperature of the water was not above 38° F., to 2 
pounds of cold water. 

The heat-carriers were platinum balls, of three sizes : 

1 of 4,200 grains = 0.6 lb. avoirdupois. 
1 of 2,800 grains = 0.41b. " 

1 of 1,400 grains = 0.21b. 



30 TRIALS OP A WARM-BLAST APPARATUS. 

Two vessels exactly similar were provided, and when duplicate 
observations were made for mutual verification, the two smaller 
balls were placed in one crucible, and the larger one, equal in 
weight to the two smaller ones, in the other. As the two instru- 
ments were sensibly alike, simultaneous observations with similar 
exposure should give, as they usually did give, temperatures 
equal within the limit of error to be expected — less than 10° F. — 
and occasionally identical temperatures. 

Sometimes one of the smaller balls was used alone, to avoid rais- 
ing the water to a final temperature above the range of a delicate 
thermometer embracing only a few degrees, of half to five-eighths 
inch to 1 degree, graduated to 0.1 degree. 

The scale of the pyrometer, for the first approximation, was for 
the larger ball (and for the two smaller balls together), 100° to 1° ; 
for the middle sized ball, 150° to 1° ; and for the smaller, 300° to 
1°. In order to ascertain what correction, if any, should be made 
for cooling during the process of withdrawing the platinum balls 
from the fire and immersing them in the water of the pyrometer, 
several experiments were made upon the effect of cooling from 15 
to 35 minutes. The fire-brick, charged with its two crucibles with- 
out the covering brick, but with the covers of the crucibles in 
place (Figs. 7 and 8, p. 37), was withdrawn from the fire in the 
usual manner, and the ball from one of the crucibles was put as 
quickly as possible into one of the pyrometers, and the notes were 
taken. The other crucible was then permitted to stand in the fire- 
brick, with its cover on, but exposed to the air of the room, usually 
15 minutes, sometimes 25 minutes, and in one case 35 minutes, 
when the balls from the crucible in question were put into the 
other pyrometer, and the notes were taken as before. 

When the two crucibles were emptied of their balls into the two 
pyrometers as quickly as possible, there were often discrepancies 
of 10°, 25°, or 50°, although accordance within 10° or less was fre- 
quent. These discrepancies resulted partly from errors of obser- 
vation, and partly, no doubt, from real difference of temperature ; 
and the apparent differences resulting from difference in the time 
of exposure to the air were therefore mixed up with errors of ob- 
servation, and with possible differences of original temperature. 
The mean cooling effect was 0.7° F. per minute, equal to 70° F. in 
the resulting temperature ; and the range was from 1.2° to 0.2°, 
say 120° to 20° in the result. At all events it was small, and 
although most active at first, while the heat was greatest, the loss 



USE OF PYEOMETER. 31 

was too small to require notice when the balls were immersed in 
the water of the pyrometer in 3 to 5 seconds from the time of 
opening the door to withdraw the fire-brick with its crucibles ; as 
was usually the case when there was no accidental detention. 

THE USE OF THE PYROMETER. 

In using this instrument we have, in order to obtain the first 
approximation, to make two assumptions : 1st, That the specific 
heat of the water at the temperatures employed, will be constant, 
and equal to 1.00000 ; 2d, That the specific heat of the platinum 
balls employed will be constant, and equal to 0.03333, that is, to 
-5 1 o that of the water. 

Since the largest platinum ball weighs three-tenths (0.3), as 
much as the water (including in all cases the heat value of the in- 
strument), it follows from the above assumptions that the heat capac- 
ity of the platinum ball will be one one-hundredth (0.01), of that of 
the water, including the inclosing vessel. Every degree, then, added 
to the temperature of the water indicates roughly 100° lost by the 
platinum ball. The error resulting from the inaccuracy of the first 
assumption is small, and may sometimes be neglected ; but with 
high temperature, where the range of temperature in the water is 
considerable, and especially when the initial temperature of the 
water is as high as 40° F., it is better to eliminate the error by the 
use of the following table of temperatures and corresponding British 
thermal units. For instance, if the initial temperature be 61°, and 
the final, 83°, the number of British thermal units added to the 
water will be : 

83.041 - 61.010 = 22.031 ; 

and the loss of heat by the platinum ball, on the second assumption 
will be : 

22.031° x 100° = 2203.1° F. 



32 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE NO. II. 

Temperatures Fahrenheit, and corresponding number of Eritish thermal units 
contained in water, from zero Fahrenheit. 



Deg. 


B. t. u. 


Deg. 


B. t. u. 


Deg. 


B. t. u. 


Deg. 


B. t. u. 


32 


32.000 


57 


57.007 


82 


82.039 


107 


107.101 


33 


33.000 


58 


58.007 


83 


83.041 


108 


1(8.104 


34 


34.000 


59 


59.008 


84 


84.043 


109 


109.107 


35 


35.000 


60 


60.009 


85 


85.045 


110 


110.110 


36 


36.000 


61 


61.010 


86 


86.047 


111 


111.113 


37 


37.000 


62 


62.011 


87 


87.049 


112 


112.117 


38 


38.000 


63 


63.012 


88 


88.051 


113 


113.121 


39 


39.001 


64 


64.013 


89 


89.053 


114 


114.125. 


40 


40 001 


65 


65.014 


90 


90.055 


115 


115.129 


41 


41.001 


66 


66.015 


91 


91.057 


116 


116.133 


42 


42.001 


67 


67.016 


92 


92.059 


117 


117.137 


43 


43.001 


68 


68.018 


93 


93.061 


118 


118.141 


44 


44.002 


69 


69.019 


94 


94.063 


119 


119.145 


45 


45.002 


70 


70.020 


95 


95.065 


120 


120.149 


46 


46.002 


71 


71.021 


96 


96.008 


121 


121.153 


47 


47.002 


72 


72.023 


97 


97.071 


122 


122.157 


48 


48.003 


73 


73.024 


98 


98.074 


123 


123.161 


49 


49.003 


74 


74.026 


99 


99.077 


124 


124.165 


50 


50.003 


75 


75.027 


100 


100.080 


125 


125.169 


51 


51.004 


76 


76.029 


101 


101.083 


126 


126.173 


52 


52.004 


77 


77.030 


102 


102.086 


127 


127.177 


53 


53.005 


78 


78.032 


103 


103.089 


128 


128.182 


54 


54.005 


79 


79.034 


104 


104.092 


129 


129.187 


55 


55.006 


80 


80.036 


105 


105.095 


130 


130.192 


56 


56.006 


81 


81.037 


106 


106.098 


131 


131 197 



The error arising from the inaccuracy of the second assumption 
is much more important, but is easily eliminated — at least approxi- 
mately — by the use of Table III., which is carried out for every 
100° F., with certain intermediate points, for reference : — 32° and 
212°, for verification of the pyrometer by these standard tempera- 
tures — melting ice and boiling water. 

At 446.2° F. the assumption of 0.03333 for the specific heat of 
platinum is correct. At lower temperatures the correction is minus : 
at all higher temperatures it is 'plus. The use of the table is obvious. 
Having found the approximate observed loss of temperature, cor- 
rected for variations in the specific heat of water, look for the near- 
est corresponding loss in column 6, " observed loss of temperature " 
etc., and if not found exactly, find the intermediate point by the 
aid of the proper difference in column 7. Opposite, in column 1, 
will be found the true loss of temperature by the heat-carrier, cor- 
responding to the observed loss. For instance, having found an 



USE OF CORRECTION TABLES. 33 

observed loss of temperature, corrected for variation of specific heat 
of water, = 2203.1°, we find in column 6, 2152.1 which subtracted 
from 2203.1, leaves 51.0; and the tabular difference for 100° being 
131.7 = 1.317 for 1°, 51 divided by 1.317, gives 38.7. Turning 
now to column 1, we find opposite 2152.1, 19C0 ; and adding 35.1 
we have 1938.1 as the (approximately) true loss of heat by the car- 
rier in cooling from initial temperature to 83° F., and 1938 + 83 
= 2021° F. as the initial temperature of the heat-carrier on its 
immersion in the water of the pyrometer. 

The manner of manipulating the platinum balls as heat carriers, 
is plainly indicated in Fig. 7. In most cases the covering brick 
maybe omitted; but it should be used whenever, on account of ob- 
stacles in the way of rapid manipulation, more than four or five 
seconds are required to remove the crucibles from the fire and to 
immerse the balls in the water. 

For observations in the heart of the fire, the crucibles may be 
used without the brick. No bits of coal must be permitted to 
enter the crucibles ; and this accident may be guarded against in 
some measure by binding on the covers with copper wire wound 
many times around. The wire will be speedily melted, but will 
endure long enough fairly to insert the crucibles and cover them 
with the glowing coal ; and, with care, they may be taken out with- 
out disturbing their covers. Thermometers should be delicate, not 
less than 0.3 inch to 1°, and graduated to tenths of a degree. 

They may then be read to hundredths, and temperatures may be 
determined within a very few degrees. 

It will be apparent, on reflection, that these tables can give only 
approximate results, and could be exact only upon the impractica- 
ble condition that the final temperature of the water and heat car- 
rier, after the immersion and cooling of the latter, should be, in 
every case, 32° F. 

But since the initial temperature must always be above this 
point, and the final temperature several degrees higher still, while 
the tables are based on the mean specific heat of platinum, or, with 
the compound balls — platinum and iron — between 32° and the re- 
spective higher temperatures included in the table, an error will 
result from the use of the tables, varying in magnitude with the 
number of degrees between 32° and the final temperature. To be 
exact, the tables should be expanded so as to embrace specific heats 
between 32° and, say, 100° F., varying by single degrees, or by 
small intervals— 3° or 5°— at the lower limit ; and 100°, 200°, 300°, 
3 



34 TEIALS OF A WAKM-BLAST APPARATUS. 

etc., as in these tables, for the upper limit. Such tables would be 
cumbrous and inconvenient, and by no means worth while. The 
approximation given by the tables is pretty close, and may usually 
be made satisfactory. In most cases a rather closer approximation 
may be made by adding the number of degrees of final tempera- 
ture of the water to the observed loss of heat by the heat-carrier, 
before correction by the table, as already described. Thus, 2203.1 
+ 83.0 = 2286.1, corresponding, in Table III, to 2001.7°. 

A still closer approximation may be made by subtracting 32° 
from the number of degrees of final temperature, and reducing the 
difference to pyrometer degrees, by multiplying it by the tabular 
difference, 0° to 100°, column 7, Table III., which is 96.9 for 100°, 
= .969 per degree. The pyrometer degrees so found are to be added 
to the observed loss of heat by the heat-carrier, and the correspond- 
ing true loss is to be taken out of the table ; and 32 added to this 
will give a close approximation to the true temperature of the hot 
ball. 

Thus, 83 - 32 = 51, and 51 x .969 = 49.4, and 2203.1 + 49.4 
= 2252.5. 

The next smaller tabular number in column 6 is 2152.1, and 
2252.5 - 2152.1 = 100.4, and 100.4 -s- 1.317 (131.7 ■*- 100 = 
1.317) = 76.23. The number in column 1, opposite 2152.1 is 
1900, and 1900 + 76.23 + 32 = 2008.2° = the true temperature 
sought— to a close approximation. The respective values found by 
the three methods are 2021°, 2002°, and 2008°, showing an extreme 
range of variation at this high temperature, of less than 1 per cent. 

Either method will usually be accurate enough. The first and 
second are equally easy of application, the third but little more 
laborious. Should more exact results be desired, the formula for 
specific heat may be used.* 

* For a discussion of the specific heat of platinum and iron, at various tem- 
peratures, or, more properly, the mean specific heat of these metals from 32° F. 
to higher temperatures, see "Journal of the Franklin Institute," Vol. LXXXIV., 
third series, July-December, 1882, pp. 91, 169, and 252. Also, " Transactions of 
the American Society of Mechanical Engineers," Vol II., p. 42 ; and Vol. III., 
p. 174. 






COEEECTION TABLE : PLATINUM. 
TABLE III. 



35 



Temperatures 


Mean sp. ht. of 


Differ- 




Differ- 


Observed loss 




in deg. Fahr. 


Platinum from 


ences of 
sp. ht. 

for each 
100° F. 


Ratio of com- 


ences of 


of temperature 


Differences 


corresponding 


32 Q computed 


puted to assumed 


by heat-carrier 


of observed 


with specific 

heats in column 

2. 


for each 100 
deg. Fahren- 
heit. 


sp. ht: viz. 1-30 
water - 0.033333. 


for each 
100° F. 


in cooling: nt 
assumed ratio 
H 2 O30toPtl. 


loss per 100° 
Fahr. 


1 


2 


3 


4 


5 


6 


7 





.031983 




.95950 




0.0 




32 


.032080 


303 


.96240 


907 


30.8 


96.9 


100 


.032286 


302 


.96857 


907 


96.9 


98.6 


200 


.032588 




.97764 




195.5 




212 


.032624 


303 


.97873 


908 


207.5 


100.5 


300 


.032891 


303 


.98872 


908 


296.0 


102.3 


400 


.033193 




.99580 




398.3 




446.195 


.033333 


303 


1.00000 


909 


446.2 


104.1 


500 


.033496 


304 


1.00489 


910 


502.4 


106.0 


600 


.033800 


303 


1.01399 


910 


608.4 


107.8 


700 


.034103 


303 


1.02303 


910 


716.2 


109.6 


800 


.034406 


304 


1.03219 


911 


825.8 


111.4 


900 


.034710 


304 


1.01130 


912 


937.2 


113.2 


1000 


.035014 


304 


1.05042 


912 


1050.4 


115.1 


1103 


.035318 


304 


1.05954 


913 


1165.5 


116 9 


1200 


.035822 


305 


1.06867 


913 


1282.4 


118.7 


1303 


.035927 


304 


1.07780 


914 


1401.1 


120.6 


1400 


.036231 


305 


1.08694 


914 


1521.7 


122.4 


1500 


.036536 


305 


1 . 09608 


915 


1644.1 


124.3 


1600 


.036841 


305 


1.10523 


915 


1768.4 


126.1 


1700 


.037146 


305 


1.11438 


916 


1894.5 


127.9 


1800 


.037451 


306 


1.12354 


917 


2022.4 


129.7 


1900 


.037757 


306 


1.13271 


917 


2152.1 


131.7 


2000 


.038063 


305 


1.14188 


917 


2283.8 


133.4 


2100 


.038368 




1.15105 




2417.2 





36 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE 111.— Continued. 



Temperatures 


Mean sp. ht. of 


Differ- 
ences of 




Differ- 
ences of 


Observed loss 




in (leg. Fahr. 


Platinum from 


Ratio of com- 


of temperature 


Differences 


corresponding 


32° computed 


puted to assumed 


by heat-carrier 


of observed 


with specific 


for each 100 


■Fr\v aqpVi 


sp. ht.: viz. l-3f' 


JXaXlOS 
■for* pppTi 


in cooling: at 


loss per 100° 
Fahr. 


heats in column 
2. 


deg. Fahren- 
heit. 


1\JL Cal^JLJL 

100° F. 


water = 0.033333. 


100° F. 


assumed ratio 
H 2 O30toPtl. 


1 


2 


3 


4 


5 


6 








306 




918 




135.3 


2200 


.038674 


307 


1.16023 


919 


2552.5 


137.2 


2300 


.038981 


306 


1.16942 


919 


2689.7 


139.0 


241)0 


.039287 


307 


1.17861 


920 


2828.7 


140.8 


2500 


.039594 


306 


1.18781 


920 


2969.5 


142.7 


2600 


.039900 


307 


1.19701 


921 


3112.2 


144.6 


2700 


.040207 


307 


1.20622 


921 


3256.8 


146.4 


2800 


.040514 


3C8 


1.21543 


922 


3403.2 


148.3 


2900 


.040822 


307 


1.22465 


923 


3551.5 


150.1 


3000 


.041129 


308 


1.23388 


923 


3701.6 


152.0 


3100 


.041437 


308 


1.24311 


923 


3853.6 


153.9 


3200 


.041745 


308 


1.25234 


924 


4007.5 


155.7 


3300 


.042053 


308 


1.26158 


925 


4163.2 


157.6 


3400 


.042361 


308 


1.27083 


925 


4320.8 


159.5 


3500 


.042669 


309 


1.28008 


926 


4480.3 


161.3 


3600 


.042978 


309 


1.28934 


926 


4641.6 


163.2 


3700 


.043287 


309 


1.29860 


927 


4804.8 


165.1 


3800 


.043596 


309 


1.30787 


927 


4969.9 


166.9 


3900 


.043905 


309 


1.31714 


928 


5136.8 


168.8 


4000 


.044214 




1.32642 




5305.6 





Table IY., which follows, constructed in the same manner as 
Table III., but for iron instead of platinum, as a heat-carrier, re- 
quires no special explanation, as the use of the two tables is alto- 
gether similar. Iron can be used at all only at moderate tempera- 
tures, and the results obtained by its use must be crude, on account 
of its rapid change of weight b}' oxidation. Table V. contains 



HEAT-CARRIERS FOR PYROMETER. 



37 



three columns of corrections : first, for platinum, corresponding to 
column 6 of Table III. ; second, for iron, corresponding to column 
8 of Table IV. ; and third, for a compound ball, composed of 700 
grains of fine wrought iron encased in 700 grains of platinum, 
formed into a solid capsule, about 0.048 inch thick; the whole 
weighing 1,400 grains, with a heat capacity (at the assumptions for 
specific heat, for Pt, 0.03333, for Fe, 0.166666), equal to that of 
4,200 grains = 0.6 lb. of platinum. The assumed specific heat of 
Fe being five times that of Pt (0.033 x5 = 0.166), the 700 grains 




Fig. 7. 

platinum balls, crucibles and fire-brick eed and cover, as arranged for 
use with the water-platinum pyrometer. 




Fig. 8. 



TOP VIEW OF LOWER FntE-BRICK. 



of Fe are equal to 3,500 grains of Pt, and 700 grains added for 
the Pt cover, the total is 4,200. 

I had two of these compound balls, and often used them at 
moderate temperatures, 1,000° to 1,200° F., in direct comparison 
with solid platinum balls, without detecting any important discrep- 
ancies in the results. The advantage of the platinum cover is that 
the iron is protected from oxidation. The advantage of the iron is 
that there is great saving of cost. 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE IV. 

FOB IRON HEAT- CARRIER : ASSUMED SP. HT. =0.166. 















Observed 




Tempera- 
tures in deg. 
Fahr., corre- 


Mean sp. ht. 
of Iron, from 


Differences of 
sp. ht. for 
each 100°. 


Ratio of 
computed to 
assumed sp . 


Difference of 
ratio for 
each 100° 


loss of 
tempera- 
tures by 
heat-car- 


Differences of 
observed loss : 


sponding 
with specific 


32° F., com- 
puted for 




ht., viz.: 
g- water — 






rier at 
assumed 




heats in 


each 100° F. 




0.16666'i 






ratio, H 2 
loFe, 
6tol. 




column 2. 


1st cliff. 


2d 
diff. 

4 


1st diff. 


2d 
diff. 

7 


1st diff. 


2d 
diff. 


1 


2 


3 


5 


6 


8 


9 


10 





.10587 




.63524 




0.0 






32 


.10687 


328 




.64122 


1966 




20.5 


65.5 




100 


.10915 


375 


47 


.65490 


2253 


287 


65.5 


70.0 


4.5 


200 


.11290 




48 


. 67743 




285 


135.5 




5.3 


212 


.11339 


423 




.68032 


2538 




144.2 


75.3 




300 


.11713 


471 


48 


.70281 


2823 


285 


210.8 


81.6 


6.3 


400 


.12184 


518 


47 


.73104 


3110 


287 


2U2.4 


88.7 


7.1 


500 


.12702 


566 


48 


.76214 


3394 


284 


381.1 


96.5 


7.8 


600 


.13268 


613 


47 


.79608 


3681 


287 


477.6 


105.4 


8.9 


700 


.13881 


661 


48 


.83289 


3966 


285 


583.0 


115.0 


9.6 


800 


.14542 


709 


48 


.87255 


4251 


285 


698.0 


125.6 


10.6 


900 


.15251 


756 


47 


.91506 


4538 


287 


823.6 


136.8 


11.2 


1000 


.16007 




48 


.96044 




284 


960.4 




12.3 


1082.5 


.16667 


804 




1.00002 


4822 




1082.5 


149.1 




1100 


.16811 


851 


47 


1.00866 


5109 


287 


1109.5 


162.2 


13.1 


1200 


.17662 


899 


48 


1.05975 


5394 


285 


1271.7 


176.1 


13.9 


1300 


.18561 


947 


48 


1.11369 


5679 


285 


1447.8 


190.9 


14.8 


1400 


.19508 


994 


47 


1.17048 


5966 


287 


1638.7 


206.5 


15.6 


1500 


.20502 


1042 


48 


1.23014 


6250 


284 


1845.2 


223.0 


16.5 


1600 


.21544 


1089 


47 


1.29264 


6537 


287 


2068.2 


240.4 


17.4 


1700 


.22633 


1137 


48 


1.35801 


6822 


285 


2308.6 


258.6 


18.2 


1800 


.23770 


1185 


48 


1.42623 


7107 


285 


2567.2 


277.7 


19.1 


1900 


.24955 


1232 


47 


1.49730 


7394 


286 


2844.9 


297.6 


19.9 


2000 


.26187 






1.57124 






3142.5 







COEEECTION-TABLE : PLATINUM-IKON. 



39 



TABLE V. 

FOR HEAT-CARRIERS OP PLATINUM, IRON, ETC. (Pt, Fe). 















Observed 






Observed 






Observed 




loss of 




True tem- 
peratures in 
deg. Fahr., 
correspond- 
ing with 


loss of tem- 
perature by 
Platinum 
heat-carrier 
at assumed 


Differences of 

observed loss 

for each 100° 

Platinum. 


loss of tem- 
perature by- 
Iron heat- 
carrier, at 
assumed 


Differences of 

observed loss 

for each 100° 

Iron. 


tempera- 
ture by 
comp'nd 
heat-car- 
rier, at 


Differences of 

observed loss 

for each 100°. 

Pt and Fe. 


observed tem- 


ratio of 






ratio of 




assumed 




peratures in 


sp. ht. H 2 






sp. ht. H 2 




ratios of 




columns 


to Pt, 
30 to 1. 






to Fe, 
6 to 1. 




sp. ht. 
Pt, -to • 




2, 5, and 8. 




2d 
diff. 




2d 
diff. 




2d 
diff. 






1st diff. 




1st diff. 


Fe, 6. 


1st diff. 


1 


2 


3 


4 


5 


6 


8 


9 


10 


























32 


30.8 


96.9 




£0.5 


65.5 




22.2 


-:o.7 




100 


96.9 


93.6 


1.7 


65.5 


70.0 


4.5 


70.7 


74.8 


4.1 


200 


195.5 




1.9 


135.5 




5.3 


145.5 




4.7 


212 


207.5 


100.5 




144.2 


75.3 




154.8 


79.5 




300 


296.0 


102.3 


1.8 


210.8 


81.6 


6.3 


225.0 


85.1 


5.6 


400 


398.3 




1.8 


29:2.4 




7.1 


310.1 




6.1 


446.2 


446.2 


104.1 






83.7 






91.2 




500 


502.4 


106.0 


1.9 


381.1 


96.5 


7.8 


401.3 


98.1 


6.9 


600 


608.4 


107.8 


1.8 


477.6 


105.4 


8.9 


499.4 


105.8 


7.7 


700 


716.2 


100.6 


1.8 


583.0 


1150 


9.6 


605.2 


114.1 


8 3 


800 


835.8 


111.4 


1.8 


698.0 


125.6 


10.6 


719.3 


123.2 


9.1 


900 


937.2 


113 2 


1.8 


823.6 


136.8 


11.2 


842.5 


132 9 


9.7 


1000 


1050.4 




1.9 


960.4 




12.3 


975.4 




10.5 


1060 


1119.5 


115.1 




1C48.4 


149.1 




1060.2 


143.4 




1082.5 


1145.9 






1083.5 




13.1 


1093.1 




11.3 


1100 


1165.5 


116.9 


1.8 


1109.5 


162.2 




1118.8 


154.7 




1200 


1282.4 


118.7 


1.8 


1271.7 


176.1 


13.9 


1273.5 


166.5 


11.8 


1300 


1401.1 


120.6 


1.9 


1447.8 


190.9 


14.8 


1440.0 


179.2 


12.7 


1400 


1521.7 


122.4 


1.8 


1638.7 


206.5 


15.6 


1619.2 


192.5 


13.3 


1500 


1644.1 


124.3 


1.9 


18i5.2 


223.0 


16.5 


1811.7 


206.5 


14.0 


1600 


1768.4 


126.1 


1.8 


2068.2 


240.4 


17.4 


2018.2 


221.4 


14.9 


1700 


1894.5 


127.9 


1.8 


2308.6 


258.6 


18.2 


2239.6 


236.8 


15.4 


1800 


2022.4 


129.7 


1.8 


2567.2 


277.7 


19.1 


2476.4 


253.0 


16.2 


1900 


2152.1 


131.7 


2.0 


2844.9 


297.6 


19.9 


2729.4 


270.0 


17.0 


2000 


2283.8 






3142.5 






2999.4 







40 TEIALS OF A WARM-BLAST APPARATUS. 

The apparatus for heating platinum heat-carriers for the pyrom- 
eter consists of two black-lead crucibles, 2 inches inside diameter at 
the top, and 3 inches deep, with suitable covers, as shown in Figs. 
7 and 8, which are set into cavities in molded fire-brick, to avoid 
danger of accidental overturns. Platinum balls, each weighing 
0.6 lb. avoirdupois (4,200 grains = 272.16 grammes), or one such 
ball, and two of 4,200 grains aggregate weight, are placed in the 
two crucibles — 4,200 grains in each—covered up, and submitted to 
the heat in the desired exposure, long enough to insure uniform 
heating throughout. If the temperature fluctuates, as in most ex- 
posures will be likely to happen, the fire-brick and crucibles will in 
some degree integrate the fluctuations during the period of ex- 
posure. 

For moderate temperatures, not exceeding a low red heat, and in 
situations not admitting of the use of crucibles, a pair of tongs was 
used, four or five feet in length, of steel, quite slender, w^ith the 
extremities of their jaws concave, of suitable form and size to re- 
ceive and cover the platinum ball. A link slipped over the handles 
held the ball securely, and permitted it to be put into places other- 
wise inaccessible, kept there until heated, and then withdrawn 
quickly and released to the water of the pyrometer. The tempera- 
ture of flue gases, and of the warm blast, determined in that way, 
agreed substantially with the readings of mercurial thermometers, 
in cases where these could be satisfactorily used. The temperature 
of the brick deep in the wall — near the inside, where the heat was 
too great for glass thermometers — was obtained in this manner. 
Many temperatures ascertained by the use of this instrument, in 
the fire, at the bridge wall, at the pier, and in the arch over w T arm- 
blast boiler No. 1, will be found under the proper head. 

2. The Calorimeter. — This instrument, shown in section in 
Fig. 9, was the result of much study, and answered fairly the 
expectations formed of it. 

The lining, which is the true containing vessel, is of 24 oz. 
tinned copper, 17 inches in diameter and 32 inches deep, with a 
rim at the top 2.25 inches wide, of the same copper ; and weighs, 
complete, 27 lbs. avoirdupois. This was surrounded, sides and 
bottom by a case of galvanized iron (Fe and Zn), 18.5 inches in 
diameter, 32.75 inches deep, No. 26 Birmingham wire gauge, 
weighing 15.5 pounds. A second case surrounds this 20 inches in 
diameter and 33.5 inches deep, of galvanized iron No. 26 w. g., 
weighing 16.1 pounds. An outside case surrounds all, 21.5 inches 



CALOEIMETER. 



41 



in diameter and 34.25 inches deep, of galvanized iron No. 18 w. g., 
weighing, with its handles, 48 pounds. There are, therefore, three 
chambers, each 0.75 inch thick, all around, sides and bottom, the 
outer one of which is filled with hair felt, the two others with eider 
down. There is a cover, also in three compartments, filled in the 
same manner. The lower compartment of the cover is a little less 
than 17 inches in diameter, and freely enters the 17-inch inner 
chamber ; the other two are 21.5 inches in diameter, and extend 




Fig. 9. 
calorimeter. 



out flush with the outside of the case. The lower plate of the 
cover, and the cylindrical band around the lower third, are of 24- 
ounce tinned copper, and weigh 3 pounds. This copper lining of the 
calorimeter and of its cover, is supposed to follow closely all the 
changes of temperature of the inclosed water, and to be to a con- 
siderable degree insulated from the exterior parts, and from the 
outer air. 

A steam surface condenser, 15 inches in diameter and 12 inches 
high, is set inside, on short legs with broad, flat feet, near the 



42 TRIALS OF A WARM-BLAST APPARATUS. 

bottom of the 17-inch chamber; so that there is a space of 1 inch 
beneath it and all around it. 

The cylindrical case of this condenser is of sheet copper, 0.18 
inch thick, and the heads are of cast brazing copper of the same 
thickness, all united by brazing. There is a 2-inch brass tube in 
the middle ; and 111: brass tubes, .75 inch outside diameter, are set 
by expanding, and sealed air-tight with soft solder, which is always, 
when the instrument is in use, immersed in cool water. This 
drum, or condenser, will safely bear an internal pressure of 200 
pounds per square inch. Steam is admitted into it by a 0.75-inch 
brass pipe near its upper end ; and water resulting from condensa- 
tion of steam is drawn off by a similar pipe placed so low as to com- 
pletely drain the lower head. Both of these pipes are made tight 
where they pass through the walls of the calorimeter, and each is 
provided with a screw- valve stop-cock. A 0.75-inch pipe, with a 
Bibb cock, is inserted in the barrel of the calorimeter, to draw the 
water out of it. 

The agitator, for insuring uniformity of temperature throughout 
the contents of the calorimeter, is constructed as follows : A brass 
pipe 1 inch in diameter, about 34 inches long, freely perforated 
with holes 0.375 inch in diameter, having at the lower end a 
pivot to rest in a suitable step at the bottom of the barrel, passes 
down through the 2-inch tube of the condenser, and rises, when rest- 
ing in its step, to about the level of the top of the cover when in 
place. A light three-legged spider, supported by light brass ears 
riveted to the lining of the barrel near the top, and having in the 
middle a short brass tube loosely fitting the tubular shaft, steadies 
the upper end of this shaft in an upright position when the cover 
is removed, and gives rise to no constraint when the cover is on. 

The cover has a bushing in the center through which passes the 
hollow hub of a miter gear of 1 inches pitch diameter, fitted to slip 
over the upper end of the tubular shaft when the cover is placed 
on the barrel. This miter gear is held in its place in the cover by 
a collar on the lower end of its hub below the cover. It is loose on 
the tubular shaft — which it is designed to turn — but is at once 
locked to it by the insertion of a thermometer-case, the upper end 
of which is provided with a stopple fitting the tubular shaft, and 
fitted with two wings which pass through slots in the upper end 
of the tubular shaft, and engage with corresponding key-seats in 
the hub of the miter gear, locking gear and shaft together. A pipe 
box, having a stand and foot riveted to the cover, carries a short 



DESCRIPTION OF CALORIMETER. 43 

1 orizontal shaft, on which, at the inner end, is a miter gear engag- 
ing with the one on the upright tubular shaft ; and at its outer end 
a crank, by means of which it may he turned, giving motion to the 
tubular shaft. 

A brass collar, fitted to slide on the shaft, carries two arms of brass 
tube, 0.625-inch diameter, screwed into the collar, serving as set- 
screws, to fix the collar at any desired height, and as supports for 
vanes to agitate the water. These arms are about 7 inches long, 
and extend to within about an inch of the lining of the barrel. The 
vanes have two blades, each secured to hubs which slide and turn 
freely on the arms, and may be set in any desired position, and at 
any desired angle, by set-screws. These vanes may, therefore, be 
considered as propeller blades, which in turning in the proper direc- 
tion give an upward motion to the water at the outer part of the 
space it fills, accompanied, of course, by an equal downward motion 
in the middle; and produce a circulation most conducive to equali- 
zation of temperature, without any alternate withdrawal and re- 
immersion of any part of the apparatus, which must always be at- 
tended by some loss of heat Some improvement could be made, 
particularly by reducing the weight of certain parts, such as the 
steam condenser, especially for low pressures — under 120 pounds 
per square inch ; but the general principles are believed to be sound, 
and the operation was fairly satisfactory. 

It should be mentioned that blocks of dry pine wood were 
placed in the spaces at the bottom, under the feet of the condenser, 
to support the heavy weight of this part ; yet this weight and the 
feet which support it are a source of great anxiety in moving the 
instrument, especially in shipping it long distances by rail, lest the 
feet should cut through the light copper lining of the barrel. A 
better plan would be to support the condenser on molded blocks of 
hard rubber of sufficient size to distribute the weight. 

It was necessary to ascertain the number of pound- of water 
which might be taken as the equivalent of so much of the metal of 
the instrument as must be assumed to follow promptly all changes 
of temperature in the contained water. Three methods were pur- 
sued for this purpose : 

1st. By direct calculation from the known weight and specific 
heat of the metals so situated ; 

2d. By drawing into the calorimeter, cooled down to a low tem- 
perature, a weighed quantity of water of a known higher temperature, 
and observing the resulting temperature — the method of mixture ; 



TRIALS OF A WARM-BLAST APPARATUS. 

3d. By condensing a weighed quantity of steam of known press- 
sure and temperature, known also to be dry saturated steam, because 
drawn from a quiescent boiler ; with a weighed quantity of water 
of known temperature in the barrel — again the method of mix- 
ture. 

By the first method we obtain : 

TABLE VI. 

EFFECTIVE HEAT VALUE OF THE CALORIMETER. 



NAMES OF METALS. 



Copper 

Tin 

Soft solder, Sn 2, Pb i 
Totals 



Weight 
Pounds. 



183.45 



Effective 

a „ Q „;~ heat 
Specific yalue . 

B. t. u. 



heat. 



171.80 


.095 


16 32 


1.2: 


.057 


.07 


8.31 


.094 


.70 


2.09 


.048 


.10 



093^ 



17.19 



fore 



The mean sp. ht. of the mass, at the usual temperatures, is there- 
17.19 



= .0937. 



183.45 
By the second method : 

We have first to ascertain the limits of error in drawing off and 
weighing water from the steam condenser, as follows : 



FIRST TRIAL. 

Weight of water poured in lbs. 11 .80176 

Weight of water drawn out " 11 .82324 

Apparent excess drawn out " 0.02148 

Ratio of excess per cent. 0.1818 

SECOND TRIAL. 

Weight of water poured in lbs. 11 . 82129 

Weight of water drawn out " 11 . 79785 

Apparent deficit drawn out " 0. 02344 

Ratio of deficit per cent. 0.1985 

THIRD TRIAL. 

Weight of water poured in lbs. 11 80566 

Weight of water drawn out " 11.82324 

Apparent excess drawn oat , ' . 01758 

Ratio of excess per cent. 0. 1483 






TESTING CALORIMETER. 



45 



Combining the errors of the three trials, we obtain : 

TABLE VII, 

ERRORS OF POURING IN, DRAWING OUT, AND WEIGHING. 





POUNDS. 


OUNCES. 


PEK CENT. 


First error 


+ 


0.02184 
0.02340 
0.01758 
0.02092 


0.349 
0.374 
0.281 
0.335 


0.1818 


Second error 




0.1985 


Third error 


+ 


1483 


Means 


0.1762 







It will be seen that the errors are in opposite directions, and that 
they include errors of pouring in and of drawing out ; and of two 
weighings. The error of drawing out and one weighing, is there- 
fore less than one-third of an ounce, less than one-fiftieth of a 




Fig. 10. 
apparatus for testing the heat capacity of the calorimeter. 



A, Cask containing about 300 pounds 

of warm water. 

B, Iron pipe and stop-cock. 

C, Thermometer in warm-water pipe. 

D, Rubber hose for warm water. 



E, Calorimeter. 

F, Platform scales weighing to ounces. 
Gr, Thermometer, graduated to \ de- 
gree F. 

H, Stand to support cask, A. 



pound, and less than one-sixth of one per cent, on quantities of 11 
to 12 pounds. The calorimeter was accurately leveled before mak- 
ing the experiments. 

In testing the heat capacity of the calorimeter by this second 
method, the apparatus represented in Fig. 10 was used. 



46 TRIALS OF A WARM-BLAST APPARATUS. 

The calorimeter was brought to about the temperature of the 
room, in order to reduce to a minimum its changes of temperature 
by external influences ; and after sufficient use of the agitator to 
bring the contained air to uniformity, readings of the central ther- 
mometer were taken once a minute during several minutes, in order 
to obtain the direction and rate of any change which might be ob- 
servable. Meantime the cask A, of capacity considerably greater 
than that of the calorimeter (which is 200 lbs.), was filled with 
water by a hose, and warmed by steam, also by means of a hose, to 
25° F. or more above the temperature of the room, only taking 
care to avoid a temperature so high as to cause rapid loss of heat 
by evaporation. After careful agitation with a stirring-stick, its 
temperature was taken, and a little drawn off, to waste, through 
the hose D (removed from the calorimeter), to bring the pipe and 
stop-cock B and the hose D to uniform temperature with the 
water. The stop-cock was then closed, and the end of the hose 
inserted in the upper end of the tubular shaft of the agitator, from 
which the thermometer and its case had been removed, as seen in 
Fig. 10 ; and the stop-cock was opened, and the water was allowed 
to flow from the cask into the calorimeter. Readings of the ther- 
mometer C were noted every 15 seconds during the filling, which 
takes 5 minutes. The temperature was pretty nearly uniform, and 
such variations as were observed, were due, it is probable, to im- 
perfect mixing. 

When the scales indicate that about the required quantity of 
water has flowed into the calorimeter, the stop-cock is closed, the 
hose is removed, the thermometer G, with its perforated tubular 
case, is replaced, the agitator is put in motion, and a set of read- 
ings of the thermometer G is taken at intervals of 1 minute (or 
less), for 5 minutes. The rate of cooling, which is regular, and 
very slow, being thus ascertained, it can be carried back to any 
desired point of time — in practice, to the time when the calorimeter 
was half full; and in a similar manner the slowly and regularly 
changing temperature can be brought forward to the same point of 
time. It is of course plain that the difference of these two tem- 
peratures at the same instant, will be the measure of the calorific 
capacity of the calorimeter. 

It is necessary to compare the two thermometers, C and G, and 
to allow for any difference which may be found in their readings 
in identical circumstances. It was found that when both were im- 
mersed in water at 95° F. to the same extent as when used in these 



TESTING CALOKIMETEK. 



47 



determinations, the latter (G) read 0.3 deg. lower than the former 
(C). The observations follow. 

TABLE VIII. 

DETERMINATION OF THE HEAT CAPACITY OF CALORIMETER. 



Time of readings by 


Headings of thermome- 


Headings of thermome-'*!^?. °L*5T^t: 


Auburndale horse- 
timer. 


ter G when calorimeter 
is empty. 


ter G after calorimeter 
is filled with water. 


rci \s ill v\aim waLCi 

while calorimeter is 
filling. 


1 


2 


3 


4 


Min. Sec. 











76.60° 






1 


76.65° 






2 


76.70° 






3 


76.75° 






4 


76.80° 






5 


Began to fill calo- 
rimeter with warm 






6 


water. 




101.6° 


7 






101.6° 


7 30 


76.975° 


98.95° 




8 






101.6° 


9 






101.6° 


10 


Filled. 




101.6° 


11 








12 




98.725° 




13 




98.675° 




14 




98.625° 




15 




98.575° 




16 




98.525° 




17 




98.500° 





By extending the range according to the ascertained rate of 
change of temperature, we obtain : 

Change of empty calorimeter per minute, 0.05° during 3.5 min- 
utes, 4 minutes to 7.5 minutes, and .05 x 3.5 = 0.175°, to add to 
76.8°, making this temperature when half the water had entered 
the calorimeter, 76.975°. 

Change of water after filling the calorimeter, 0.05° per minute 
during 4.5 minutes, to be carried back 4.5 minutes, from 12 min- 
utes to 7.5 minutes, and .05 x 4.5 = 0.225°, to be added to 
98.725°, making 98.950°. 

Temperature of warm water before entering the calorimeter, 
101.6°. 

Weight of calorimeter and water, pounds 489.125 

Weight of empty calorimeter, without thermometer and 

i 315.250 

Weight of warm water put in 173.875 



48 



TBIALS OF A WARM-BLAST APPARATUS. 



To the temperature ascertained by thermometer G, we must add 
0.3°, by which amount it read lower than thermometer C, making : 
76.975 + 0.3 = 77.275, and 
98.950 + 0.3 = 99.250. 
Corrected for the varying specific heat of water, the correspond- 
ing number of British thermal units is set opposite each tempera- 
ture, respectively, in the following table : 



TABLE IX. 

QUANTITIES OF HEAT IN BRITISH THERMAL UNITS. 





Degrees. 


B. t. u. 


Calorimeter, at half full 


77.275 
99.25 
101.6 


77.3056 


Water, calorimeter half full 


99.3278 


Water before entering calorimeter 


101.6848 







Then : 



x = 



(173.875 + 18.61) x (101.6848 - 99.3278) 



101.6848 - 77.3056 
129.485 x 2.357 



24.3792 



=192.485 x .09668 = 18.61. 



The value of x = 18.61, the quantity sought, has to be found by 
a few trials, beginning with 17.19, found by the first method, which 
proves to be too small by 0.8 per cent, to satisfy the conditions of 
the equation. 

Nine other similar determinations gave, with the foregoing, the 
ten following values: 18.09, 18.61, 18.50, 18.92, 19.06, 19.10, 
19.20, 18.40, 18.55, 19.42. 

The mean of all is 18.78 

To this add for solder put on afterward, 2.09 lbs., sp. ht. = .048. . .10 
Calorific value of calorimeter as ascertained by the second 
method 18.88 

This is nearly 10 per cent, more than was found by the first 
method, p. 719, which was 17.2. 

By the third method : 

At 5 hours 45 minutes p.m., when for an hour no steam had 
been drawn from the boiler, while steam pressure at about 51.6 
pounds per square inch by a test guage had been steadily main- 
tained, the steam must be considered as substantially " dry, satu- 



HEAT CAPACITY OF CALOKIMETEK. 49 

rated steam." It could not be " superheated," because there was 
no superheating surface ; and it could not contain much suspended 
water in liquid form, because there had been no ebullition for an 
hour, and the ebullition caused by drawing off to the calorimeter 
45.4 cubic feet of steam — less than one-half the cubic contents of 
the steam space — through a f-inch pipe, must have been very 
slight. 

Account of the experiment to determine by the third method the 
heat capacity of the calorimeter. 

Height of mercurial barometer, inches 29 . 51 

Atmospheric pressure ; lbs. per sq. inch 14.494 

Steam pressure by steam gauge 51.6 

Steam pressure, absolute 66 . 094 

Number of B. t. u. contained in one pound of steam of 

66.094 lbs. per sq. inch pressure, absolute 1205. 1060 

Temperature to which water condensed from steam was 

reduced in the calorimeter 85 . 75° 

Number of B. t. u. contained in water of temperature 

85.75° 85 . 7965 

Number of B. t. u. surrendered by each 1 lb. of steam on con- 
densation and cooling to 85.75°, 1205.1060 - 85.7965 = 1119.3095 
Quantity of water from condensed steam, drawn off and 

weighed on coin scales, lbs 7.238 

Total number of B. t. u. given up by 7.238 pounds cf 

steam; 1119.3095 x 7.238 = 8101. 5C22 

Temperature of water in calorimeter before admitting 

steam, degrees F 48.45 

Number of B. t. u. contained in each 1 lb. of this water. . 48.453 
Number of B. t. u. gained by each 1 lb. of this water in 

rising from 48.45° to 85.75°, 85.7965 - 48.4530 = . . . 37.3435 
Total number of B. t. u. imparted to the water, divided 

by the number of B. t. u. gained by 1 lb., 8101.5622 -r- 

37.3435= 216.9470 

Weight of water in calorimeter. 200.0000 

Water value of calorimeter, lbs 16 . 9470 

This result is only 1.47 per cent, less than the result obtained by 
the first method, and is strongly confirmatory of that result ; espe- 
cially in view of the fact that several experiments made in circum- 
stances nearly similar, gave " saturated steam " when the value 
17.2 was used for the calorimeter. 

This third method is entitled to much weight, because it is pre- 
cisely the method pursued in ordinary use. Yet it seems hardly 
probable that this value can be less than we have found it to be by 
direct calculation, by the first method (p. 719) ; and I have there- 
4 



50 



TEIALS OF A WARM-BLAST APPAKATDS. 




fore adopted as the heat-equivalent of the calorimeter, in the follow- 
ing calorimetric work, in terms of water, 17.2 pounds. 

The work done with this instrument, will be found in the sequel. 
3. The Anemometer. — The germ, and perhaps something more 
than the germ, of this beautiful instrument, is to be found in Weis- 
bacirs Lehrbucli der Ingenieur- wad Maschinen-Mechanik, Braun- 
schweig, Friedrich Yieweg und Sohn, 1857, vol. 2, pp. 734, 735, 
under the name of the Wollaston Anemometer. In its present 
form, it is the joint production of Mr. F. H. Prentiss and the 
writer, although the principal share belongs to Mr. Prentiss. 

Two glass tubes (Fig. 11), about 30 inches long, about 0.1 inch 
diameter inside and 0.7 inch outside, are connected 
at each end bv means of stuffing-boxes, to suitable 
brass attachments, through which they are secured 
to a backing of wood. 

These attachments, at top and bottom, have each 
a tubular opening, with a stop-cock in the middle of 
its length, which can be turned at will to establish a 
free communication between the glass tubes, or to 
shut off all communication. Directly over each tube 
a brass drum-shaped vessel is placed, 4.25 inches in 
length and of equal diameter. The heads of these 
drums, at both ends, are formed of plate glass, prop- 
erly secured with screw-rings, and made tight with 
suitable packing. A tubular opening extends up 
from each glass tube to the drum above it, and there 
is a hole in each drum, directly in line with the axis 
of the glass tube, each fitted with a stop-cock and a 
nipple for attaching a flexible pipe. Two sliding 
scales are arranged between the glass tubes, to meas- 
ure, the one depressions, the other elevations of the 
surface of a liquid filling the lower half of the tubes, 
indicated in the cut, Fig. 11, near the middle of the 
height. Both stop-cocks are represented in the cut 
as closed. 

The lower one being opened the two tubes, in 
communication at their lower ends, are filled up to 
about the middle of their height with a mixture of 
alcohol and water, care being taken to avoid wetting 
the interior of the upper end of the tube poured through — the 
pouring being done through a small glass tube inserted through 





Fig. 11. 

.^TilOMETEE. 



DESCRIPTION OF ANEMOMETER. 51 

the hole at the top of the drum, from which the stop-coek is re- 
moved for this purpose. The filling-tube is now to be raised so 
that its lower end is a little above the surface of the alcohol and 
water, the lower stop-cock is to be closed, and the upper one opened ; 
and crude olive oil is to be carefully poured in until it fills the 
first tube up to the upper cross-tube into the second tube, and so 
finally fills both tubes and rises to about the middle of both drums. 

The crude olive oil is of an olive-green color, and forms with the 
colorless alcohol and water a beautiful and very deep meniscus, if 
the tubes are clean, and the filling has been done with sufficient 
care, making the line of demarkation very distinct. Neither liquid 
discolors the glass, and if up-and-down motions are made cautious- 
ly and slowly, the liquids do not mix, and the common surfaces 
remain undisturbed. The specific gravity of the oil should be de- 
termined in advance, as it may vary a little, although we found it 
quite uniformly 0.916. The specific gravity of the alcohol and water 
may be made anything desired, between that of water, 1.000, and 
that of absolute alcohol, 0.813 ; but must always be made greater 
than that of the olive oil. 

Where extreme delicacy is desired, the difference may be as small 
as 1 per cent. ; that is, if the oil be as above, .916, the mixture of 
alcohol and water may be, .926. If the difference be much less 
than 1 per cent., the upper and lower liquids have a tendency to 
get into confusion, and do not constantly maintain a distinct line 
of demarkation at their common surface. For many purposes, a 
difference of specific gravity as great as 2 per cent, will give suffi- 
cient sensitiveness — fifty times as much range as a water column — 
and is more convenient to use. 

The method of using this instrument to ascertain the force of 
chimney draft or other air current, is as follows : If both the 
stop-cocks between the tubes are opened, and both the small stop- 
cocks on the top of the drums are also opened, so that the surface 
of the oil in both drums alike is open to the air, both liquids will 
come to a level ; the oil in the drums, very obviously, and the heav- 
ier mixture below the oil as certainly, if not quite as obviously ; 
since if higher in one tube than in the other, the united weight of 
the two liquids in that tube must be greater than in the other, and 
must cause the liquid to sink down and flow into the other tube, 
raising the surface of the oil in the drum over that other tube, and 
causing it to flow across to the first tube, until both liquids are 
brought to a coincident height in the two tubes. 



52 TRIALS OF A WARM-BLAST APPARATUS. 

A slight difference will, however, commonly be found in the 
height of the lower liquid, owing to the unequal capillarity of the 
tubes, since these can rarely be obtained sufficiently near alike in 
caliber to avoid, when in equilibrium, a small, but sensible differ- 
ence of level, which must be ascertained and allowed for. 

If, now, the upper stop-cock between the tubes be closed, the 
lower one being left open, the surfaces of the two liquids will retain 
their respective heights in the two tubes, so long as the surface of 
the oil in the two drums remains subject to equal pressure. But if 
one drum be put in communication with a flue or chimney, by 
means of a flexible or other tube connected with the nipple of the 
small stop-cock — this stop-cock being open — while the other drum 
remains open to the air through its open stop-cock, the diminished 
pressure, due to chimney draft, upon the surface of the oil in that 
drum, will cause the oil to flow up into the drum, under the prepon- 
derating weight of the air on the surface of the oil in the other drum. 

The surface of the oil in the drum is about 100 times as large as 
the inside cross-section of the glass tubes, and in the same propor- 
tion will the rise of the lower liquid on the one side, and its de- 
pression on the other, exceed the corresponding rise and depression 
of the upper surface of the oil. 

If now, when equilibrium has been restored, the lower stop-cock 
be closed and the upper one opened, and the connection with the 
flue or chimney be severed — say by removing the flexible tube from 
the nipple — the lower liquid will be kept immovable, while the oil 
will flow through the upper cross-tube, and come to a common 
level in the two drums. On connecting the nipple again with the 
flue or chimney, and again closing the upper stop-cock and opening 
the lower one, a diminished repetition of the former action will 
take place ; the lower liquid will rise a little in one tube and fall 
a little in the other, and the surface-level of the oil in the two 
drums will again become slightly unequal. This inequality, which 
will be much less than before, may be again removed by the same 
method ; and a very few repetitions of this process will bring the 
difference in level of the surface of the lower liquid in the two 
tubes (corrected for inequality of capillary attraction, as explained 
above), to represent the entire difference in pressure on the sur- 
face of the oil in the two drums, due to the draft of the chimney ; 
that is, a certain known height of column, filled, in one tube with 
a mixture of alcohol and water of specific gravity 0.920, with the 
flue-pressure resting on its surface, is just balanced by an equal 



DELICACI' OF ANEMOMETER. 53 

height filled with olive oil of specific gravity 0.916, with the press- 
ure of the atmosphere resting on its surface. The differential col- 
umn, therefore, represents a water column one-hundredth part as 
high, or a column of mercury y^g-Q- part as high. A draft which 
would be measured by 0.01 inch of mercury, or by 0.136 inch of 
water, would, on this anemometer, be measured by 13.5 inches of 
differential column. It is therefore a hundred times as sensitive as 
a water column, and more than 1,300 times as sensitive as a mer- 
cury column. If too sensitive, so that the required range would 
exceed the limits of the instrument, its sensitiveness can be re- 
duced to any desired extent by a larger admixture of water, or by 
the use of pure water, as described by Weisbaeh, in which latter 
case the difference of specific gravity will be (1.000 — 0.916) = 0.084, 
and the sensitiveness 11.9 times as great as that of water alone, and 
160 times as great as that of a mercury column. 

This instrument with the respective specific gravities 0.937 and 
0.916, difference, 0.21, equal to 2.1 per cent, was sensitive enough 
to show plainly the reduction of chimney draft caused by opening 
a sliding register in the fire-door for the admission of air above the 
fire, giving an aggregate open area of no more than six square 
inches. An instrument of such delicacy for determining pressures 
affords the best attainable data for estimating the velocity of air 
currents, far superior to the Casella revolving anemometer, or any 
other known to me. I will only add that after trying almost every 
applicable substance for packing the stuffing-boxes around the ends 
of the glass tubes, rings of cork, cut out of sheets of fine cork 
0.25 inch thick, of suitable size to go tight over the tubes without 
bursting open, and to go easily into the stuffing-box, answered best ; 
that is, they stopped all sensible leakage ; but there was still a slow 
waste of alcohol — and perhaps of water also — by insensible leakage, 
and evaporation on coming to the air. The compression of the 
cork was very great ; six rings of 0.25 inch each — 1.5 inches in the 
aggregate — were compressed into a thickness of less than an eighth 
of an inch. Too much care cannot be taken to make all joints and 
stop-cocks tight. All passages through the brass should be drilled, 
and to this end, the turns at the lower end should be rectangular, 
instead of curved quarter-turns, as shown in Fig. 11. 

4. The Incased Aneroid. — This is simply a fine aneroid ba- 
rometer, 8.12 inches outside diameter, 2 inches in thickness, put into 
a brass case, resembling the case of a large steam gauge, fitted with 
a stout ring, by means of which a plate-glass cover is made air tight. 



54 TBIALS OF A WAKM-BLAST APPARATUS. 

A 3-way cock at the bottom, connected by a flexible tube with a 
pipe inserted in a flue, affords facility for observing, alternately, 
and as often as desired, the difference between the barometric press- 
ure of the external air, and the rarefied air within the brass case, 
outside of the aneroid, when the cock is open to the flue. Each 
inch of mercury is represented by an arc 2.21 inches in length, 
divided to tenths and fiftieths. Each of the smaller divisions is 
therefore equal to .044 inch, and to 1.12 millimeters, and is easily 
divisible by the practiced eye, to tenths, equal to .002 inch mercury, 
representing say 0.001 lb. pressure per square inch, and to .0277 
inch of water. A hole 0. 5 inch diameter, properly located in the back 
of the case, and stopped with an air-tight screw-plug, gives access, 
on removing the plug, to the adjusting screw of the aneroid, so 
that the latter can be compared — and if it need be adjusted — by 
the mercurial barometer. This instrument was found convenient 
and useful. 

5. The Mercurial Barometer. — This was an ordinary " Sig- 
nal Service" barometer, by J. & H. J. Green, New York, with 
freshly boiled mercury, and in all respects in good order. All ob- 
servations were corrected for temperature, by attached thermometer. 
The floor of the boiler room is about 37 feet (11.28 meters), above 
mean tide in Boston harbor, and the barometer itself, as observed, 
40 feet. This elevation is equal to 0.0456 inch of mercury and to 
0.093 lb. per square inch. The mean weight of the atmosphere 
is therefore: 29.9218-0.0456 = 29.8762 inches, and to 14.696 
— 0.093 = 14.603 lbs. per square inch. Lawrence is 26 miles N. 
by W. from Boston, in Lat. 42° 42' 30" N., Long. 71° 10' 0" W. 
The value of g (the force of gravity) is 32.163. 

6. The Hygrometer. — This was the wet-and-dry bulb " Hygro- 
phant," of J. S. F. Huddleston, Boston. The observations were 
reduced by Guyot's Tables, 3d edition, Smithsonian Institution, 
Washington, D. C. 

7. Thermometers. — These were many in number, and in con- 
siderable variety ; all which were used for purposes requiring ac- 
curacy being tested by Mr. J. S. F. Huddleston, Boston. All were 
graduated to the Fahrenheit scale, some to half degrees, some to 
one-fifth degree, and some to one-tenth degree. One long and deli- 
cate thermometer, sole survivor of its class, is described as follows : 

Whole length 31.5 inches. 

Length of bulb (mean) 2.3 " 

Diameter throughout 0.25 " 



WINCKLER APPARATUS: GEISSLER BULBS. 55 

Length of graduated stem 28 inches. 

Graduated, range, 19° to 83° = 64°. 

Graduated to nj degree. 

Whole weight 1405 grains. 

glass, 80.5$ 1132 " 

Hg, 19.5$ 273 " 

Sp. ht. glass, .1923 ; Hg, .0290, mean, .1705. 

1405 x .1705 
Heat value, ~qqq = .034 B. t. u. 

This thermometer was used with the steam calorimeter, as were 
others similar to it, which were hroken. Being accurately cali- 
brated and carefully divided, .4375 inch to 1°, 0.487 = 1.11 milli- 
meters to 0.1°, it may be read with much confidence to 0.01°. It 
is not to be supposed that actual temperatures, above 0° F. could be 
determined by it to this degree of accuracy ; but differences of 
temperature, within a moderate range, as in calori metric experiments, 
may be considered as correct within less than 0.01° at each reading, 
say 0.02° in the observed range. On a range of 10°, as in pyrometry, 
this would be 0.2$. On a range of 50°, as in calori metry, 0.04$. 

8. The Winckler Apparatus. — This clever and convenient in- 
strument for ascertaining, approximately, the quantity of carbon 
dioxide (CO g ) in flue gases, by the volumetric method, will not 
be described, as it exists, so far as I know, in only one form, and 
is to be obtained from dealers in chemical instruments, apparatus 
and materials. It is not delicate enough to determine the quantity 
of carbon monoxide (CO), but will detect traces of it when 
present. 

But this gas will newer be found in more than very minute quan- 
tities in any reasonably well-managed fire, and for the convenient 
and expeditious determination of the C0 3 , and consequently of 
the quantity of atmospheric air per pound of carbon (and per 
pound of coal, if the composition of the coal is known), the 
"Winckler apparatus is very valuable. It was used in these experi- 
ments only as an auxiliary — the C0 2 and CO being ascertained 
throughout by the more accurate gravimetric method. 

9. The Geissler Bulbs. — These are used in determining both 
the C0 3 and the CO in flue gases, by the gravimetric method, and 
are seen suspended from the scales, and also in place in the appa- 
ratus, in Fig. 17 (to be introduced in the sequel). I remark only 
that they should be of large size, in order to deal with considerable 
quantities of the absorbed gases. 

10. The Chemical Balance. — This, also, should be of large size, 



56 TKIALS OF A WARM-BLAST APPARATUS. 

to weigh 200 milligrammes without injury to the scales ; and of 
the best quality obtainable. The one used in these experiments, 
was made by H. Troemner, Philadelphia, weighing up to 200 
grammes, = 3086.5 grains, or about 0.44 lb. av., divided to weigh 
to tenths of a milligramme, but capable, by skillful manipulation, 
of weighing to twentieths of a milligramme (.00005 gramme). 

11. The Steam Gauge. — A 10-inch Bourdon steam gauge, made 
by the American Steam-Gauge Company, compared with a mer- 
cury column — as often before — both before and after the experi- 
ments, was put into a position where it could not be affected by heat 
from the boilers, and kept shut off except at the time of quarter- 
hourly readings. Every opening of the stop-cock, to let the press- 
ure come to this gauge, produced an instantaneous lowering of the 
pressure in the small pipe leading from the boiler, and recorded 
itself by a slight mark on the trace of the Edson recording press- 
ure gauge — a very satisfactory check upon the accuracy of the 
readings in point of time. 

12. The Edson Pressure- Recording Gauge. — Continuous 
tracings from this instrument — night and day — were taken, and in- 
tegrated, for comparison with the record of the test gauge. 

A set of these tracings, for one week, will be found reproduced 
hereafter. 

Some other minor pieces of apparatus will be briefly described, 
so far as necessary, in connection with the account of their use. 



III. 

It is proposed next to present a general summary of results, 
followed by a condensed record of the weekly experiments. 



RESULTS OF EXPERIMENTS. 



57 



GENERAL SUMMARY OF RESULTS. 



Pacific Boiler : Cold Blast, 
W abm-Blast Boiler No. 1 : 
Warm-Blast Boiler No. 2 
"Pacific Boiler." 



Natural Draft. 

Abstractors with double tubes. 
Abstractors with deflectors, applied to the 



The results with anthracite, in the Pacific boiler, are the means 
for five weekly trials ; all the others are for single weekly trials. 



table x. 



Coal consumed, net, per week : 

Pacific Boiler 

Warm Blast No. 1 , 

Warm Blast No. 2 

Water evaporated per week : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Pounds of water per pound of coal : 

Pacific Boiler 

Warm Blast No. 1 , 

Warm Blast No. 2 

Mean temperature of feed water : 

Pacific Boiler (Fahr.) 

Warm Blast No. 1 

Warm Blast No. 2 

Mean temperature of external air, days : 

Pacific Boiler (Fahr.) 

Warm Blast No. 1 

Warm Blast No. 2 •. 

Steam gauge pressure above atmosphere, pounds per 
square inch : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Mean barometric pressure, pounds per square inch : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Steam pressure, absolute : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 



Anthracite. 


Bituminous. 


16264 
20368 
16740 


12890 
15184 


147039 
180542 
157483 


121590 
14507J 


9.04 
8.86 
9.41 


9.43 
9.55 


71.90° 

38° 
49° 


72.40° 
36° 


78.3° 

34° 

49° 


71° 
34.2° 


47.54 
54.40 
42.50 


47.30 
64.40 


14.47 
14.64 
14.70 


14.61 
14.66 


62.01 
69.04 
57.20 


61.91 
79.06 . 



58 



TEIALS OF A WAEM-BLAST APPARATUS. 



TABLE X. 



Pounds of water evaporated from and at 212° F., per 
pound of coal, days and nights : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 



Water evaporated from and at 212° F. by day, per 
pound of coal burned during days and nights : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 



Evaporative power of coal : 

Pacific Boiler 

Warm Blast No. 1. ... 
Warm Blast No. 2 



Efficiency, days and nights, per cent. 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Efficiency, days, per cent. 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 



Efficiency 
cent. : 



water, days ; coal, days and nights, per 



Pacific Boiler 

Warm Blast No. 1. 
Warm Blast No. 2. 



Losses : per cent., complement of efficiency 
days only ; coal, days and nights : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 



water, 



Losses, per cent. , at chimney, by radiation from brick- 
work, and by imperfect combustion, = CO : 

Pacific Boiler, chimney 

Radiation 

CO 



Warm Blast No. 1 chimney 

Radiation 

CO 



Warm Blast No. 2, chimney. 

Radiation 

CO 



Anthracite. 


Bituminous. 


10.51 
10.81 
11.12 


10.58 
11.54 


9.34 
10.00 
10.77 


9.22 
10.72 


13.56 
13.45 
13.61 


14.27 
14.30 


77.48 
80.37 
81.74 


76.73 

80.70 


79.96 

87.05 
87.76 


76.53 
84.21 


68.87 
74.35 
79.20 


64.61 
74.96 


31.13 
25.65 

20.80 


35.39 
25.04 


17.75 
2.64 
2.13 

22.52 


17.03 
3.39 

2.85 


23.27 


15.00 
4.00 
0.63 


14.24 
4.00 
1.06 


19.63 


19.30 


12.83 
4.00 
1.43 




18.26 





KESULTS OF EXPEKIMENTS. 



59 



TABLE X. 



Temperature of smoke-box, Fahr. : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Temperature of air supplied to furnace : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Temperature of escaping gases. 

Pacific Boiler. 

Warm Blast No. 1 

Warm Blast No. 2 

Gases cooled by abstractors : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Air warmed by abstractors : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Temperature of steam, days : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Difference of temperature, boiler and gases : 

Pacific Boiler, gases above boiler 

Warm Blast No. 1, " below " 

Warm Blast No. 2, " below " 

Difference of temperature, boiler and air supply : 

Pacific Boiler, air below boiler 

Warm Blast No. 1, " above " 

Warm Blast No. 2, " above " 

Pounds of flue gases per pound of coal, days : 

Pacific Boiler 

Warm Blast No. 1 

Warm Blast No. 2 

Pounds of water equivalent in heat capacity to flue 
gases per pound of coal ; sp. beat of gases = 0.238. 

Pacific Boiler 

W T arm Blast No. 1 

Warm Blast No. 2 

British thermal units carried off in gases per pound of 
coal, days : 

Pacific Boiler. 

Warm Blast No. 1 

Warm Blast No. 2 



Anthracite. 


Bituminous. 


368.3° 
396.9° 

377° 


376.9° 
397.4° 


78.3° 
337.7° 
334° 


71° 
349.5° 


368.3° 

189° 
164° 


376.9° 
196 3 


0° 
207.9° 
213° 


0° 
201.4° 


0° 
303.7° 

285° 


0° 
315.5° 


297.5° 
361.1° 
291.2° 


297.3° 

322.6° 


70.8° 
127.1° 
127.2° 


79.6° 
126.6° 


219.2° 
21.6° 

42.8° 


226.8° 
26.9° 


22.39 
23.49 
24.17 


25.23 

28.37 


5.33 
5.59 
5.75 


6.00 
6.75 


1576 
866 
661 


1835 
1092 



60 



TEIALS OF A WARM-BLAST APPARATUS. 



TABLE X. 



Efficiency corrected for difference in temperature of 
external air, and difference in time of banking fires: 

Pacific Boiler per cent. 

Warm Blast No. 1 

Warm Blast No. 2 

Difference of Efficiency : Points gained by warm 
blast, over Pacific Boiler, cold blast : 

Warm Blast No. 1 

Warm Blast No. 2 

Ratio of gain to tlie larger quantity (f|".^ =11.9$ etc.) 

Warm Blast No. 1 per cent. 

Warm Blast No. 2 

Ratio of gain to the smaller quantity (-^^ = 13.5$ 
etc.): 

Warm Blast No. 1 

Warm Blast No. 2 



Anthracite. 



68.87 
78.18 
81.43 



9.31 
12.56 



11.9 
15.4 



13.5 

18.2 






Bituminous. 



64.61 
77.59 



12 98 



16.7 



20.1 



The power consumed in driving the blower is about 1 per cent, 
of the whole power produced by the boiler in combination with a 
good steam engine. 

It therefore appears that the net saving effected by the warm 
blast was from 10.7 to 15.5 per cent, of the fuel used with cold blast, 
which is the same thing as to say that discontinuing the warm blast 
would cause an increased consumption of fuel equal to from 12.3 
to 18.9 per cent, of the quantity used with hot blast. Broadly 
stated, the gain is 10 to 15 per cent. 



^»^ 



IV. 



CONDENSED RECORD OF WEEKLY EXPERIMENTS. 



The following tables are greatly condensed, embodying, as they 
do, the summing up of more than 1,250 pages of notes taken dur- 
ing the tests, and the results of very laborious calculations. Table 
XI., occupying eleven pages, is progressive, the successive sections, 



CONDENSED BECOBD OF EXPERIMENTS. 61 

numbered at the left hand 1 to 38, requiring for their full explana- 
tion only preceding sections. Observe, that the line " Mean, for 
anthracite," gives for the Pacific Boiler (cold blast), the means of 
the first 5 weeks, A, B, C, D, E ; and for the Warm-Blast Boiler, 
the means of the first and third week, G and I — the single weeks, 
F and H, are to be compared with the corresponding means. 



62 



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Mean of all 



CONDENSED RECORD OF EXPERIMENTS. 



68 



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64 



TRIALS OF A WARM-BLAST APPARATUS. 



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65 



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CONDENSED EECOED OF EXPERIMENTS. 



67 



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68 



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and nights; steam, days only; coal, 
burned davs and nie-hts 




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CONDENSED RECORD OF EXPERIMENTS. 73 

The line "Mean of all," in each section, has not much signifi- 
cance, especially in sections relating to fuel, but may be found con- 
venient in a general way. 

Table XII. is the result of duplicate analyses, with repetitions in 
cases where the duplicate results appeared to be too discrepant. 
The anthracites were remarkably uniform, as, indeed, were the 
bituminous samples. The marked character of each kind of coal 
will be noticed. 

In Table XIII. the hygrometric observations w r ere reduced by 
Guyot's tables, each by itself, and a mean was taken of the results. 

Tables XIV. and XY. are the result of continuous duplicate 
analyses of the flue gases, through each forenoon, each afternoon 
(except Saturday p.m.), and each night. Bottled samples were also 
taken simultaneously, for verification of results in cases of too great 
discrepancy between the two simultaneous duplicates. 

Observe that, in the middle division of these tables, the sums of 
the figures in lines 1, 2, make the quantities in line 3, and that 
these correspond to the first line in the upper division ; the sums 
of the figures in lines 4, 5, make the quantities in line 6, corre- 
sponding to line 2, upper division ; the sums of the figures in lines 
7, 8, make the quantities in line 9, corresponding to the third line 
in the upper division ; and that the sums of the figures in lines 2, 
5, 9, 10, make the quantities in line 11. Finally, the figures in 
wide-face type, lines 3, 6, 9, 12, make 100.00. 

In the lower division, the figures in lines 1, 2, those in lines 4, 5, 
and those in lines 6, 7, added together, make in each case 100.00. 
The quantities, or ratios, in line 8, are simply 100 times the quo- 
tient of the numbers in line 7, divided by those in line 6. 

In line 10, the O combined with hydrogen in the coal, disappears 
in desiccating the gases, and does not appear in the dry gases. 

All necessary details concerning the manner of arriving at the 
several values inserted in these tables, will be found in the sequel. 



74 



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ANALYSIS OF FLUE GASES. 



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MEASUREMENT OF HIGH TEMPERATURES. 77 

Pyrometric Measurements of Temperatures. — All tempera- 
tures ascertained by the use of the water- platinum pyrometer, here- 
tofore described, are embodied in the following tables, and these 
tables, in turn, are graphically represented in the accompanying 
diagrams. Temperatures were taken at both boilers, but the 
greater number, probably, at Warm-Blast Boiler No. 1, since 
special provision was made in the setting of that boiler for con- 
venient use of the pyrometer. The high temperatures in Table 
XYI. were taken at Warm-Blast Boiler No. 2 (which was 
" Pacific Boiler" remodeled to warm blast), more than two months 
after the close of the last weekly experiment, ending May 20, 
1882. My assistants went to Lawrence on a morning train, took 
matters just as they found them in the regular daily use of the 
boiler, and obtained the results in this table — partly melting the 
platinum balls in experiment 6 — probably the result of some slight 
impurity in the platinum. I have used, for the most part, the 
temperatures obtained by the first (and simplest) method of reduc- 
ing the pyrometric observations to degrees F., partly because that 
method gives a result a little too high, in most cases — not more 
than 1 per cent, too high — and we are sure that the heat-carrier can 
never be hotter than the flame or other source of heat to be meas- 
ured, and may be a little cooler. 



78 



TBIALS OF A WABM-BLAST APPABATUS. 



TABLE XVI. 

PYROMETRIC OBSERVATIONS OF TEMPERATURES AT WARM- BLAST BOILER NO. 2, 
JULY 28, 1882. OBSERVATIONS NOS. 1, 2, 3 AND 4, AT BRIDGE WALL. NOS. 5 
AND 6 IN THE HEART OP THE FIRE. 





Temperature 
of water in 
pyrometer, 
2.1053 lbs. 


Number of 

British thermal 

units in 

water above 

0°F. 


HEAT-CARRIER. 


Observed loss of 
temperature by 

heat-carrier 
at assumed ratio 
of sp. ht. for 
Pt, 30 to 1, 
for Fe, 6 to 1. 
See Table VI. 


True loss of 

temperature 

and true 


OES. 


Kind of 

Metal. 


Ratio of 

water to heat 

carrier. 


of heat- 
carrier when 
taken from 
the fire. 


1 


2 


3 


4 


5 


6 


7 


1 


96.65 

81.20 


96.71995 
81.28740 

15.48255 

99.3779 

84.4418 

15.9361 

102.59753 
85.44580 


Pt. 

Pt. 
Pt & Fe. 
Pt & Fe. 

Pt. 

Pt. 


105.265 
105.265 
105.265 
105.265 
105.265 
107.7 


1629.8 

1677.5 

1805.5 

1779.16 

30-35.1 

3455.4 


1488.3 
96.7 


2 


15.45 

99.3 

83.4 


1585.0 

1526.9 
99.3 


3 


15.9 

102.51 

85.40 


1626 2 

1496.8 
102.5 


4 


17.11 

103.02 
86.16 


17.15173 

103.10906 

86.20782 


1599.3 

1483.1 
103.0 


5 


16.86 

110.30 

81.54 


16.90174 

110.41090 

81.57808 

28. 83282 

113.121 
81.037 

32.084 


1586.1 

2546.0 
110.3 


6 


28.76 

113. 
81. 

32. 


2856.3 

2835.2 
113.0 




2948.2 



Mean of 1 and 2 = 



1585.0 + 1626.2 



1605.6. 



* O A A 15993 + 1586 -! 1*00 » 

Mean of 3 and 4 = ^ = 1592.7. 



« h « o a 1605.6 + 1592.7 _.. iK 
Mean of 1, 2, 3, 4 = ^ = 1599.15. 



at * k a a 2656.3 + 2948.2 OOAO OK 
Mean of 5 and 6 = r = 2802.25. 



About one-sixth of the platinum was fused in observation 6, and cooled in 
drops, like shot ; and one drop adhered to the lip of the pyrometer, and did net 
enter the water at all— a circumstance which raised the "ratio" to 107.7. 



HIGH TEMPERATURES OBSERVED. 



79 



TABLE XVII. 

TEMPERATURES DEDUCED PEOM PYROMETRIC OBSERVATIONS IN TABLE XVI., BY 
THE SECOND AND THIRD METHODS, AS DESCRIBED ON p. 45. THE THIRD 
METHOD IS A LITTLE THE MOST ACCURATE. 





SECOND METHOD. 


THIKD METHOD. 


NO. OF 
OBS. 


Observed 
loss, plus 
final tem- 
perature of 
heat-carrier. 


True tem- 
peratures by 
eecond 
method, 
deg. Fahr. 


Final tem- 
peratures 
minus 32° F. 
in deg. F. 


Ratio 

pyr. to 

Fahr. 

deg. 


Final temp, 
minus 32° 

F., reduced 
to pyrom- 
eter deg. 


Observed 

loss, plus 

final t. above 

32° in py- 
rometer (leg. 


True tem- 
peratures by 
third 
method, 
deg. Fahr. 


1 


2 


3 


4 


5 


6 


7 


8 


1 


1629.80 
96.65 


1566.3 
1606.7 
1546.6 
1534.1 
2623.0 
2911.3 


96.65 

32. 


.969 = 62.65 
.969 = 65.21 
.969 = 68.32 
.969 = 68.82 

.969 = 75.87 


1629.80 
62.65 


1538.9 
32.0 


2 


1726.45 

1677.50 
99.30 


64.65 x 

99.3 
32. 


1692.45 

1677.50 
65.21 


1570.9 

1579.3 
32.0 


3 


1776.80 

1805.50 
102.51 


67.3 x 

102.51 
32. 


1742.71 

1805.50 
68.32 


1611.3 

1530.1 
32.0 


4 


1908.01 

1779.60 
103.02 


70.51 x 

103.02 
32. 


1873.82 

1779.16 

68.82 


1562.1 

1517.6 
32.0 


5 


1882.62 

3035.10 
110.30 


71.02 x 

110.30 
32. 


1847.98 

3035.10 

75.87 


1549 6 

2599.1 
32.0 


6 


3145.40 

3455.40 
113.00 


78.30 x 

113.0 
32.0 


3110.97 

3455.40 

78.49 


2631.1 

2888.1 
32. 




3568.40 


81.0 x 


.969 = 


= 78.49 


3533.89 


2920.1 



The " true temperatures," in columns 3 and 8, are found by the use of Table 
VI. (except Nos. 5 and 6, which go too high for Table VI., and are obtained from 
Table IV.), in the manner explained on p. 36. Observe that in Nos. 1, 2, 4 and 
6, the platinum heat-carrier was used ; and Nos. 3 and 4, the compound, Pt, Fe, 
heat-carrier. The three methods do not give results very discrepant. The first 
method gives temperatures a little too high ; the second a little too low ; the 
third, usually a little nearer correct. The greatest differences occur with the Pt, 
Fe heat-carrier. 



80 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE XVJII. 

TEMPERATURES AT BRIDGE WALL, ASCERTAINED BY THE USE OF THE WATER- 
PLATINUM PYROMETER. DEGREES FAHRENHEIT. 







TIME. 


Tem- 






TIME 


Tem- 






TIME. 


Tem- 


DATE 






pera- 


DATE 






perature, 
deg. F. 


DATE 






pera- 










ture, 


















ture, 


1881. 


h. 


m. 




deg. F. 


1881. 
July 


h. 


m. 




1881. 

July 


h. 


m. 





deg. F. 


July 










8 


10 


30 


A.M. 


787 


11 


11 


30 


A.M. 


1431 


14 


4 


40 


P.M. 


1445 




10 


30 




808 




12 


31 


P.M. 


1536 




4 


50 




1419 




11 


40 




1097 




12 


31 




1427 




5 






1279 




11 


40 




1153 


12 


4 


35 




1363 




5 


10 




1332 


9 


9 


50 




1095 




4 


45 




1381 




5 


20 




1262 




9 


50 




991 




4 


55 




1251 




5 


20 




1056 




11 






735 




5 


15 




1249 


15 


11 


35 


A.M. 


993 




11 






770 




5 


30 




1185 




11 


50 




883 




11 


11 




985 


13 


3 


20 




1339 




12 


5 


P.M. 


915 




11 


11 




953 




3 


30 




1266 




3 


40 




1327 




11 


11 




1018 




3 


40 




1322 




4 






1258 




11 


11 




1045 




3 


50 




1377 




4 


15 




1017 




12 




M. 


1112 




3 


55 




1236 




4 


25 




728 




12 






1129 




4 


7 




1222 




4 


40 




799 




12 






1023 




4 


15 




1186 




5 






894 




12 






1105 




4 


25 




1154 




5 


25 




862 




1 


45 


P.M. 


1342 


14 


9 


20 


A.M. 


1056 




5 


45 




741 




1 


45 




1345 




9 


30 




1056 




5 


45 




653 




1 


45 




1322 




9 


40 




1026 


18 


10 


5 


A.M. 


1216 




1 


45 




1296 




9 


50 




1205 




10 


25 




1406 




4 






1386 




10 






1259 




10 


45 




1376 




4 






1382 




10 


10 




1172 




11 


15 




1296 




4 






1324 




10 


20 




1208 




11 


50 




1474 




4 






1305 




11 


20 




1472 


19 


1 


25 


AM. 


*526 




4 


55 




894 




11 


35 




1239 




1 


25 




535 




4 


55 




974 




11 


45 




1320 




10 


20 




1260 




5 


55 




1024 




11 


55 




1329 




11 


5 




1381 




5 


55 




1050 




12 


5 


P.M. 


1418 




11 


20 




1305 


» 


8 


30 


A.M. 


1431 




12 


15 




1259 




11 


35 




1222 


» 


8 


30 




1310 




2 


25 




1438 


21 


12 


30 


A.M. 


*653 


* 


8 


30 




1303 




3 


45 




1447 




12 


30 




*674 


* 


8 


30 




1366 




3 


55 




*1611 


22 


12 


30 


A.M. 


*537 


11 


10 


30 




1409 




4 


5 




1404 




12 


30 




*556 




10 


30 




1479 




4 


20 




1289 


23 


1 


30 


A.M. 


*537 




11 


30 




1557 




4 


30 




1318 




1 


30 




*556 



* Date not recorded. 



* Perhaps 100° too high. 



Fires banked. 



This table is represented graphically, as a profile in Fig. 12, the temperatures 
being represented as ordinates at equal distances, but in the same order as in this 
table. The temperatures for July 14 are represented graphically in Fig. 13, 
with the ordinates properly spaced to represent the respective times at which 
they were taken. 



TEMPEEATUEES ES FUENACE. 



81 



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v 



TRIALS OF A WARM-BLAST APPARATUS 




TEMPERATURES : WARM AND COLD-BLAST BOILERS. 



83 



TABLE XIX. 



PYROMETRIC MEASUREMENTS OP TEMPERATURE EST ARCH OVER "WARM-BLAST 
BOILER NO. 1 ; FEBRUARY 13, 1882. 



TIME. 


TEMPERATURE 
OP "WATER. 


INCREASE OP HEAT. 


HEAT-CARRIER. 


RESULTING 
TEMPERATURES. 


h. 
m. 

Part 

of 

Day. 


At im- 
mersion 
of heat- 
carrier. 


After 

cooling 

of 

heat- 
carrier. 


In de- 
grees F. 


In British 
thermal 

units. 


Kind of 
metal. 


Eatio as- 
sumed of 

water 
to heat- 
carrier. 


Lost hy 
heat car- 
rier in 
cooling. 


Tempera- 
tures sought 
in degrees 
Fahr. 


1 


2 


3 


4 


5 


6 


7 


8 

630.2 
611.8 

588.4 
498.8 
658.4 
668.1 
811.2 


9 


8:22 a.m. 

8:45 

2: p.m. 

2:34 

3: 3 

3:33 

4:27 


71.3 

77.6 

77.22 

82.8 

86.9 

92.6 

80.6 


77.7 

83.8 

83.17 

87.8 

93.6 

99.4 

89.0 


6.4 
6.2 
5.95 
5.0 

6.7 

6.8 

8.4 


6.4098 
6.2114 
5.9609 
5.0100 
6.7134 
6.8180 
8.4164 


Pt. 
Pt. 
Pt. 
Pt. 
Pt. 
Pt. 
Pt. 


100 

100 
100 
100 
100 
100 
100 


7u7.9 
695.6 
671.6 
586.6 
752.0 
767.5 
903.2 



The highest observed temperature of superheated steam in the 

boiler, was 344° F., and the highest temperature of the iron must 

344° + 903° 
have been about midway, say, • ^ = 624°, or perhaps a 



2 



ittle higher 



TABLE XX. 

COMPARISON OF TEMPERATURES FOUND WITH PACIFIC AND WARM-BLAST BOILERS. 



LOCATION OF TEMPERATURES. 



In heart of fire 

At bridge wall 

At pier ... 

In smoke-box 

Air admitted to furnace , 

Steam and water in boiler 

Gases escaping to chimney 

External air 

Gases cooled, Warm-Blast Boiler 
Air warmed, Warm-Blast Boiler 



temperatures: 
degrees fahr. 



Pacific 
Boiler. 



2426° 
1341° 

368° 

78° 

292° 

368° 

78° 



Warm- 
Blast 
Boiler. 



2796° 
1599° 
895° 
377° 
334° 
300° 
164° 
34° 



Differ- 
ence. 



370° 

258° 

9° 
256° 

8° 

204° 

44° 

213° 

300° 



Before any just or useful comparison can be instituted between 
the several figures in Table XX. it will be necessary, or at least 
convenient, to reduce them all to a common basis — 1° temperature 



84 TRIALS OF A WARM-BLAST APPARATUS. 

of external air. This will affect many of the other figures. For 
simplicity and convenience, we will reduce this, in both cases, to 
0° C, = 32° F., which will reduce the temperature in the case of 
the Pacific Boiler, 78° - 32° = 46°, and in the case of the Warm- 
Blast Boiler, 34° — 32° = 2° F. A corresponding reduction would 
result in the temperature of the fire; but here another equalization 
is required. 

The temperature of the heart of the fire is affected chiefly by 
two causes, namely : First, the quantity of air passing through the 
fire per pound of coal burned; and, second, the temperature of this 
air. For the latter, we merely subtract, as above mentioned, 46° 
from the temperature in the case of the Pacific Boiler, and 2426° 

- 46° = 2380° ; and in the case of the Warm-Blast Boiler, 2796° 

- 2° = 2794°. 

But these temperatures were found in different quantities of air: 
21.28 pounds of air per pound of coal, in the former case, and in 
the latter, 20.36 pounds. Taking this last quantity in both cases, 
and assuming the anthracite coal to be in such a state of ignition 
that the hydrogen it may have contained has all been consumed, 
and neglecting the moisture in the air, we have, 0.238 being the 
specific heat of air, and also the gases of combustion ; 0.82 the 
proportion of carbon in the coal, and 14,544 B. t. u. the full heat- 
ing power of 1 pound of carbon : 

14544 x 0.82 _ 11926.08 _ . 
20.36 x .238 ~~ 4.84568 " 

This will be the increment of heat, in degrees F., in passing 
through the fire in both cases ; to be added in the one case to 32°, 
and in the other case to 332°, the difference, 300°, being due to 
heat derived, in the abstractor, from the outflowing gases, in the 
Warm-Blast Boiler. Then : 

Pacific Boiler 2461° + 32° = 2493° 

Warm-Blast Boiler 2461° + 332° = 2793° 

Difference 2793° - 2493° = 300° 

There will be less difference at the bridge wall, as the tempera- 
ture tends to equalize itself with that of the boiler, and this tend- 
ency is the more rapid the greater the difference between the fire 
and hot gases on the one hand, and the boiler and its contents on 
the other. I arrive at the following mean temperatures, under 
equal conditions : 



COMMON BASIS OF TEMPERATURES. 85 

AT THE BRIDGE WALL. 

Pacific Boiler 1340° P. 

Warm-Blast Boiler. . . 1600° F. 

Difference, 1600° - 1340° = 260° F 

The temperature at the pier, we found 895° (Fig. 12), and the 
corresponding temperature for the warm blast is 1050°. We then 
have : 

FLUE GASES : 

At the pier, about to enter flues, 

Warm-Blast Boiler 1050° F. 

Pacific Boiler 895° F. 

Difference, 1050° - 895° = 155° F. 

Discharged to chimney, 

Pacific Boiler 373° F. 

Warm-Blast Boiler 162° F. 

Difference, 373° - 162° = 221° F. 

The temperature at the smoke-box will depend chiefly on that of 
the steam and water in the boiler ; and that, in turn, depends in 
great measure on the rapidity with which steam is drawn off. We 
will assume the temperature of the steam to be 300° F., which is 
not very far from the mean, corresponding to 67.2 pounds pressure 
per square inch, absolute, and to about 52.5 pounds steam-gauge 
pressure. (The mean, for the Pacific Boiler, was 47.50, and for 
the Warm-Blast Boiler, 53.77.) The corresponding temperature in 
smoke-box, we have found to be 377° for external air at 34° (Table 
XX.), and for 32° we may properly call it 375° F. We have 
found the temperature in smoke-box, Pacific Boiler, to be 368° with 
47.5 lbs. the square inch mean steam pressure, corresponding to a 
temperature of 285° in the boiler. Adding 5°, to bring it up to 
our assumed temperature, 300°, we have 368° + 5° = 373° F. ; that 
of the Warm-Blast Boiler being, as we have seen, 375° F. The 
gases discharged from the Warm-Blast Boiler to the chimney, we 
have found to be at 164°, with external air at 34°, and we may call 
them, for air at 32°, 162° F. 

We may now reconstruct our table, on a basis of equal temper- 
ature of external air, and throw its numbers into the form of a 
diagram, fairly representing the comparative temperatures in the 
two boilers (Fig. 14). 



86 



TRIALS OF A WARM-BLAST APPARATUS. 



Diagram of Comparative Temperatures. 



1367.2 C. 



In Fire. 



In Fire. 



2793: 



1533.9 C. 



2500 F. 



1371.1 C. 



2000 F. 



1093.3 C. 



726.7 G. 



1340 F. 



Bridge Wall 



J600JL 
1500°F. 



jm.ic_._ 

815.6°C. 



Bridge Wall. 



Pier. 



J050F. 
"lOOOF." 



5 65.6 O. 

~537.8°C. 



479.4 C. 



895 F. 



-461.2 F. 



260 C. 




=2&ECL- 



Absolute 



■461.2 F. 



-247 C. 



Fig. 14. 



COMPARATIVE TEMPERATURES. 



87 



TABLE XXI. 

COMPARATIVE TEMPERATURES — PACIFIC AND WARM-BLAST BOILERS UNDER EQUAL 
CONDITIONS; 20.36 POUNDS OP GASES OF COMBUSTION — IN THE FIRE — PER 
POUND OF ANTHRACITE COAL, 82 PER CENT. CARBON, COMPLETELY BURNED 
TO C0 2 : EXTERNAL AIR AT 32° FAHR., STEAM PRESSURE, 52.5 POUNDS PER 
SQUARE INCH ABOVE THE ATMOSPHERE — TEMPERATURE OF STEAM, 300° F. 



LOCATION OF TEMPERATURES. 



In heart of fire 

At bridge wall 

At pier 

In smoke-box 

Air admitted to furnace 

Steam and water in boiler 

Gases escaping to chimney 

External air 

Gases cooled, Warm-Blast Boiler 
Air warmed, Warm-Blast Boiler 



temperatures: 
degrees fahr. 



Pacific 
Boiler. 



2493° 

1340° 

895° 

373° 

32° 

300° 

373° 

32° 



Warm- 
Blast 
Boiler. 



2793° 

1600° 

1050° 

375° 

332° 

300° 

162° 

32° 



Differ- 
ence. 



300° 
260° 
155° 

2° 
300° 

0° 
211° 

0° 
213° 
300° 



It will be observed that the air entering the furnace is wanned 
300°, while the gases are cooled only 213°. This difference, or 
something like it, was constantly observed, and may be explained 
by two causes : First : , the weight of the gases was about one-twen- 
tieth greater than that of the incoming air, by reason of the carbon 
carried off as C0 2 , and (the specific heat of the gases and of air 
being sensibly alike — 0.238), this circumstance alone would bring 
the cooling of the gases down from 300° to 285° ; second, the whole 
mass of brick and iron composing the abstractors was kept at a 
pretty high temperature by conduction from the boiler setting. 

This would tend, of course, to raise the mean between the out- 
going gases and the incoming air ; that is, to aid the warming of 
the air, and to retard the cooling of the gases. The mean tem- 
perature of the air in abstractor was (32° at entering, 332° at leav- 



ing)* 



32° + 332° 



= 187°. The mean temperature of the gases in 

375° + 162° 



abstractor was (375° at entering, 162° at leaving), 



2 



= 268.5° ; and 268.5°- 187.0° = 81.5°. 

When the air enters at 32°, the gases are leaving at 162° ; and 
162° - 32° = 130°. 

When the air leaves, to enter the furnace, at 332°, the gases are 
entering from the smoke-box, at 375°, and 375° - 332° = 43°. 



The mean 



130° + 43 c 



= 86.5°, is about the difference to be ex- 



88 TEIALS OF A WARM-BLAST .APPARATUS. 



pected between two fluids on opposite sides of iron plates, the one 
imparting heat to the other, at the rate of conduction necessary in 
steam boilers. It may, perhaps, be reduced to 75°, but it is prob- 
able that the enhanced cost of the apparatus would be out of pro- 
portion to the gain. 

Table XXI. is graphically represented in Figs. 14 and 15. The 
former sufficiently explains itself, as the several temperatures in 
Table XXI. are merely located at their proper respective positions, 
according to the scale chosen. 

The base line is the absolute zero of temperatures, 461.2° F. be- 
low zero Fahrenheit, equal to 274° C. below zero centigrade. The 
spaces shaded by heavy vertical lines represent the respective 
quantities of heat carried off by the chimney. 

Fig. 15 represents the same temperatures as they stand related 
to the surfaces of the shell and flues of the boiler, and to the flues of 
the abstractors, by means of which heat is withdrawn from the gas- 
eous products of combustion, and imparted to the water in the boiler. 

The diminishing rate of absorption with reduction of tempera- 
ture, as the gases approach the temperature of the absorbing sur- 
faces, is clearly shown. 

The gases are, in fact, cooled by the air in the abstractor 138° 
F. below the temperature of the steam in the boiler, but a very 
large area is required to do this. 

Incidentally, Fig. 15 shows the relative volume of the gases of 
combustion at successive points. Calling the volume at the tem- 
perature of external air (32° F.), equal to 1, it is 6 to 6.6 in the 
heart of the fire, 3.65 to 4.18 at the bridge wall, 2.75 to 3.06 at the 
pier, on entering the boiler-flues, 1.69 at the smoke-box, and 1.26 
at the blower, where it is discharged to the chimney. 

These two diagrams, Fig. 14 and Fig. 15, are a complete sum- 
mary of the experiments recorded in these pages, so far as they relate 
to the two modes of boiler setting, with cold blast and warm blast, 
applied to boilers otherwise exactly alike, under equal conditions. 

Analysis of Coals. — The manner of obtaining and preserving 
samples of coal has been already described. A suitable portion of 
each sample to be analyzed, separated from the rest with the pre- 
cautions usual in assaying to insure a fair representation of the 
whole sample in the part selected, was put into a platinum " boat," 
weighed, inserted in a glass tube about •£ inch caliber and 24 inches 
long, and kept at a gentle heat — a little above 100° C. — in the fur- 
nace seen in Fig. 17, with a stream of air passing through the 
tube, to desiccate the coal, until after repeated trials, it came to 






COMPAEATIYE TEMPEEATURES. 











>, 










!s 






Diagram of Temperatures 


Volumes and Surfaces. 










h 


























































































s °« 










a ™ 










3 1! 










1 a 










CO 111 

*2 &. 










PI p 1 










11 c&5 










•fi «S «fi >* 
















f J 










I 










3 ** 


















— O 


















o ■" 


















> c 


















-d .2 


































5 £ o ° CO 


















Temperat 
ucts of Cc 
5 passed o 
ast Boiler 
oiler v Cold 
a.2. 




■s 






— 




a; s 








?o 85 ffl z 




^t : 










** a. 42 E £ « 




■gj-sj 1 








*0 » 3 != *o 2 












delation ■ 
e gaseou 
of the S 
EG, We 
F G, Pa. 
,. Abstrac 




ifl 










£ g O X 




«■§! 


-■—*—- 


— - — 






"o 5 < CQ C3 




^i ft 














^! 5 : f~" 


— 






















Ji-i 




































t « 1 












°! -5' f 


fa 



































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6" r> ! -3 


£ 










SI !L_-fe — 


■ ._ . ■?_ 










s ,'fa':f .* 


°! 










<£'/ w 












-,||S.| c 

In i' 


T 






















u]l J ^_ 












g it 1 

1 *u s 


5' 










III! Lis 


p 
N 










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^ / fa 












• ♦ P i7 i °^ 














fa si g 














°8 h: / i 


























iO /PI 












v^ 


1 ! 








f 








|~u — 


— — 




h 


* £ fa' 

S 1 






// i 






I//T 














1/7 »..' «~ 




x 


« 


« 


s s 


M 


1 


S !//" J «i " 




g 


J 


1 


E S 
"0 




3 

^o 


"S / 


// i P?. 




1 **'' r^ ~ 




> 


o 

> 


£ 


r* r» 


> 


'to 


•^ /i/ • 

J3 // __J^ |3 




1 




! 

1 
j 




1 


j 
i 
\ 

1 


! jfT~T 

4 //"";"* '[■ 


- — 


u«l 




•i* 


fa'l 


Pai 


"*\ 


]f/ ■ 1 




5 =0| 




!fe 


°|| 


I 


>*jL 


s^>/ ! 






^^u.. wj ; "kg I -501 




\< 




iia = 


oi J— — h"^-- 




•■aid 0} ;H«d4 1 ^p^a 


1 



Fig. 15. 



90 TEIALS OF A WARM-BLAST APPARATUS. 

constant weight, when it was supposed to be dry. The tube was 
then connected with a can containing compressed oxygen, the heat 
was increased, by means of the fifteen Bunsen burners of the fur- 
nace, to a moderate red heat, and a stream of oxygen was passed 
through the tube, until after repeated trials, the boat and its con- 
tained coal again came to constant weight — the carbon (and any 
other combustible substances which may have been present), hav- 
ing been oxidized, leaving in the boat ash only. 

The use of oxygen instead of atmospheric air facilitates the oxi- 
dation, greatly shortens the process, and not only saves the time of 
the assistant, but, most important of all, lessens in a still greater 
degree the danger of losing an analysis through the premature 
breaking of a tube — a circumstance happening with vexatious fre- 
quency when air is used. All analyses were made in duplicate, 
and in case of suspicious difference, or of accident to one boat, 
they were repeated until satisfactory agreement was reached. 

Passing, after leaving the tube, through a calcium chloride tube 
and a set of Geissler bulbs, the oxygen leaves its water, derived 
from oxidation of the hydrogen, in the former, and its C0 2 , de- 
rived from the oxidation of the carbon, in the latter. The four 
chief ingredients of the coal — carbon, water, ash, and hydrogen, 
being thus determined directly, by weight, the remaining possible 
ingredients — oxygen, sulphur, and nitrogen are, in the anthracites 
left undistinguished, as a residuum, small in amount, only about 
2.8 per cent, in the aggregate. In the bituminous coals, the deter- 
mination of the sulphur, less than 1 #, and of the oxygen, 4.5 to 5fo 
(in one case), leaves the nitrogen as a residuum, 2 fo. 

The continuous reservation of samples — at every firing — the 
systematic preservation of these samples, their uniform treatment, 
and the great number of duplicate analyses, give reason for consid- 
erable confidence in the final mean results. 

Calorimetric observations to determine the quantity of entrained 
water in the steam. — The full notes of all experiments with the 
calorimeter, made during the entire week, July 11-16, 1881, are 
subjoined, together with the calculations of results. These experi- 
ments were made at various stages of the fire, and under varying 
conditions of demand for steam, and of rising and falling, and 
stationary pressure, and are supposed to represent fairly the usual 
operation of the Pacific Boiler in this respect. In a few instances, 
noticeably in the three observations on July 14, there is a slight ir- 
regularity in the first reading of the thermometer, " after admitting 
steam," column 7, due, perhaps, to imperfect mixing ; but subse- 
quent readings are clear. 



CALOBIMETEIC OBSEEVATIONS. 



91 



CALORIMETRY : QUALITY OF STEAM. 


o • 
6 « 

CD ^ 
i oa 

IS 

&H H 


o 


6< 

co OS 

a co 

co 


hi 

ill 


C5 


8 JS 

02 


H o « 
R g 


00 


CD 
fcfi 

« 00 


P3 
H 
H 

h 

o 

& 

■< 
K 

Ph 

9 
s 

EH 


<<3 


I> 


Deg. F. 

86.575° 

86.55° 

86.525° 

86.5° 

86.475° 


as 
la 


CO 


Deg. F. 

57.85° 

57.875° 

57.9° 

57.925° 

57.95° 


R 

03 

g 

R 

^ M 

H 

o 

H 




in 


w CO 
h5 lO 


o 

a 

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l-l JO 


« . 
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H H 

Si 
og 

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Eh O 

a o 
Sr 

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Is 

<U 61) 


CO 


Lbs. av. 
521.0625 

let on. 
shut off. 


SI 


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Lbs. av. 
515.625 

Steam 
Steam 


fa 


03 
C5 
53 

fq M 

H 
B 


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JO o 

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< •• CO CO 

tH 



92 



TBIALS OF A WAEM-BLAST APPARATUS. 









CAL0EIMTERY 


: QUALITY OF STEAM. 






















<?■-> 


H 




.s" 














O • 
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<- 02 
b* H 


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. 






CALOEIMETRIC OBSERVATIONS. 



93 



CALORTMETRY : QUALITY OF STEAM. 


i OB 

<i S 

DO 


o 


P. o 

02 


hi 


OS 


OQ 

■a 

1 § 

CO 


H & 


00 


ti to 

« 3 


P5 

H 

ft 

O 

H 
K 
P 

SI 

B 

B 

1 


IN 


£> 


rv] iO iO io °o °o 

R o ©5 i> CQ i> <^> 

tJH CO CN* Oi T-l -i-l 

fcJO • 

« tJI CO CO CO CO CO 
fl Ci C5 OS C5 Ci OS 


PQ 


» 


o o o IO 
w r> o O? lO i> CO 

?> oc oo oo co oo 

be ...... 

4> tHH ^H ^44 ^ ^ ^ 

O Tf ^ ■* ^* Tt< Tf 


R 

OQ 

« 

M 

si 

Eh 

a 
2 

N 


Si 

PQ-o 


JT5 


> CO 

30 £> 

i-l OS 


u 

8 


Tf 


J OS 


« . 

Eh ^) 
H Eh 

° a 

*i 

» a 

°s 

Eh O 

a-fl 


£.2 
<** 


eo 


a; O S ° 

^ CM o *=> 


is 

2 to 
o g 

pq 


©* 


od °. mm 


EH 


o3 
1 


- 


00 00 

jia o o 

SoOf-t<NC0^j. • • O 1> 00 Oi o 

<< .. ^ O 1-< 

OJ 



94 



TRIALS OF A WARM-BLAST APPARATUS. 



CALORIMETRY '. QUALITY OF STEAM. 


H 

E* P< 
m 


O 


.2 

£ to 

3 10 
p. t- 

to 

,0 


5 

2 * 


C5 


CO 

8 ° 

O r-> 

O w 
0) 
GO 


e 1 

5 I 

E-i 


00 



P CD 


K 

H 

ft 

O 

1 

« 

W 
Ph 

a 

Eh 


II 


i> 


Deg. F. 

102.625° 

102.6° 

102.55° 

102.5° 

102.45° 

102.4° 




to 


Deg. F. 

38.175° 

38.225° 

38.275° 

38.325° 

38.375° 

38.4° 

38.45° 


n 

H 

P. 

c a 

o < 
E-i 

w 

2 


PQ-o 


*a 


> c* 

<Z CO 


6 


c 

i 

>» 

pp 


•* 


. JO 

«3 GO 

CO w 

M rH 


H 
11 

►J ;a 

-« z 

Hg 

a a 
2o 


CO 

3 w: 


eo 


J2 € 


a; oo 

£P 


Ci 


. }2 c3 2 

> S3 © © 

^ mm 

^ 1-1 





go* 



■I 


- 




• IO CO CO 

»h h e« eo ^ • • t- 00 

«* .. ** W *- ' 

* CO 






CAL0EI1IETEIC OBSEEYATIOXS. 



95 



calorimetry: quality of steam. 


<1 \ £ « 

r 7 ° t. 


< 


x" 

B IO 

! *- 


z r 

E ? 


X 


01 

- T* 


< 
< 

1 


J| - | s £ b b b h 

5* 


- = - fc- o 01 IO J> 

= -S 1 -, 1 . t 1 io ia *o w 

-_ * - t£ 

d m g H: ;£ 3£ :r :£ 


■ 
z 

z 

< 

D & 

x 


it r! 

— — 





■ 00 


= 
- 

— 


-r 


SB X 


: i 

J z 

S z 


Si 

= .= 
<** 


s; 


= 3 fcj 

POS — 

1— 1 ■ 


— r- § — - — ♦= 


i 


■ 
Z 

"cE 

< 


■FH 


. L~ IO 

£~©^-i«cc-^»o:oi>coc> 






TKIALS OF A WAKM-BLAST APPABATUS. 



CALORIMETRY : QUALITY OF STEAM. 




o 


.s 

to CO 

P- ^ 

CO 

fit 


3 . 


OS 


GO 

P O 
CO 


8 1 

« fe 3 

B°| 


00 


,• JO 

00 

If ^ 

A 00 


O 

1 
1 

H 

w 

1 


is 

ra qq 

£ p 


t- 


Deg. F. 

86.4° 

86.4° 

86.35° 

86.35° 

86.3° 

86.3° 


J. . 

li 

pq 


co 


Deg. P. 

51.5° 

51.5° 

51.25° 

51.55° 

51.575° 



H 
t& 

?! 

P 

o S 

U -9) 
O GO 

H 

w 

2 


a>5p 
£ o 

pq^ 


IO 


co '30 
►-) CO 


o5 
o 

P 

0) 

i 


■^ 


M CO 


B g 

H O 

2p 

£«4 


li 


eo 


Lbs. av. 
524.25 

let on. 
shut off. 


w 

pq 


<N 


Lbs. av. 
517.5 

Steam 
Steam 


1 


03 

O 

1 


- 


• JO o 

SoorHOjco^iocor^ooos 
^ CO w 



CALOKIMETKIC OBSERVATIONS. 



97 



CALOEIMETRY : QUALITY OF STEAM. 


B 

O • 
P B 

o f 

■ 03 

a as 

B P 
1 





a 

03 C- 
OK 


►3 

K & I 

b ° £ 


Oi 


03 

(3 IO 

8 « 

02 


b 

B K 
B 2 

K & :5 
1°B 

5 % 


00 


bj) 

A CO 


« 

B 

B 
O 

s 

K 
& 

Eh 

«J 

K 

B 
Ph 

B 
Eh 


ii 

03 be 


i> 


ft J> IO OJ £- lO OJ 

O IO IO IO T}H "* "* 

M • ■ 

a> £- i> i> i> £> *> *> 

fi OOOOOOOOQOGOGC 


11 





00 

5/ IO O IO l-O O 

^ <M IO i> CQ IO 

CQ Ci 03 CO CO 
be ..... 

a> ^ H ^ ,_ ,_, 
H IO 10 10 to 


A 
B 

03 

B 

g 

t? . 

B B 
O H 
03 
E- 

w 


B 


pq-o 


m 


03 tH 


a5 


a 

6 


TT 




1! 

a 

H 
g3 


Ii 

i: a 
3 s 


CO 


£S id 

03 »o a" ° 

►JO ° 3 




<N 


1 1 

O306 « « 

J 10 


g 


03 



B 
PS 


- 


• w 10 

Sr-iOTH(MCO'^ , '^fiOOi>0005 
"^ IO CO 



98 



TRIALS OF A WARM-BLAST APPARATUS. 






CALORIMETRY : QUALITY OF STEAM. 


STEAM-GAUGE 
PKESSURE. 


o 


X rH 

fe OS 

ft ^ 
x 

5 


< 

w o 2 


C5 


90 

3 « 

w 


g g 


qo 


& 13 

to 


K 
W 

h 


H 

« 
P 
f- 

< 

i 

s 
w 

E- 


a -s 


t> 


W »3 £^ C4 o t> 13 £J 

CD C, O 1(5 ^ ^* ^ 

o> t^ bo t> t> t> *> *> 

Q i> fc~ t- i"- fc» i> t- 


Is 

gfcJO 


» 


«/ 13 o »3 
« o <M 13 i> 

C5 Ci 05 05 o 

to ... 

« t> i> *> «> 00 
P CO CO CO CO CO 


n 

w 

ft 

o < 

o£ 

a 
o 

H 


J2W 
_j e 


1Q 


. 00 

3^ 


o 

Q 
0) 

I 

pq 


<# 


x CO 

5 *> 


Kg 

PS ? 

S o 

c i 

SP 


fa 

B 35 

03 X 

0) to 
£ c 


CO 


13 

>• « 

.CO • o 

° 2 1 


fl 

2 ? 

pq 


c* 


S 3 

>£ Is 

Xi t- 
13 


K 

M 


DC 

o 


- 


o 
* oo or^c^co^^iocot-aoosOT-j 

< .. 00 Ti ri 

OS 









CALORIMETEIC OBSERVATIONS. 



99 



CALORIMETRY : QUALITY OF STEAM. 




o 


C7 1 

ft CO 

•J 


1 


Oi 


-3 

8 05 
03 


DIFFERENCE 

OF 

TEMPERATURE. 


00 


^ OS 
ft 3 


Eh 

ft 

O 

H 
K 

« 

E 




t~ 


Deg. F. 

93.075" 

93.45" (?) 

93.° 

92.975° 

92.925° 

92.9° 

92.875° 


5* 


eo 


Deg. F. 

43.5" 

43.525" 

43.55° 

43.575° 

43.6° 

43.625° 


n 

w 

en 

H 
R 

g" 

E- 

w 

o 


pq-a 


la 


> 00 

* s 

m CO 

>A 05 


6 
o 
c 

1 
■a 
>. 
pq 


-tf 


H 00 

=» co 

■J 05 


K • 
S« 

E- » 

o g 

*£ 

E- O 

a » 
« » 


<43 


eo 


Lbs. av. 
525.25 

let on. 
shut off. 


Id 

of 
pq 


n 


Lbs. av. 
515.5625 

Steam 
Steam 




O 

g 


- 


S^O-pH<MCO^COCO^OOOOt-<C3 
* ©3 O 



100 



TRIALS OF A WARM-BLAST APPARATUS. 



^5 



CALOKIMETKY : QUALITY OF STEAM. 


gg 

03 


o 


.s 

OQ O 

ft o 
w 




OS 


03 

I 9 

02 


8 g 
g £ 

fe g 


00 




fe lO 
W CM 

<s § 


K 

ft 

o 

H 
B 

« 
B 


03 ^ 

5« 


t- 


Deg. F. 

86.2° 

86.1° (?) 

86.05° 

85.975° 

85.95° 

85.9° 


li 

4) 03 

m 


«o 


Deg. F. 

35.35° 

35.375° 

35.4° 

35.425° 

35.45° 

35.475" 


n 

H 
Q 

la 
SB 

° 03 

E-i 

w 

O 




»n 


h? OS 


8 

s 

o> 
03 

ft 


>* 


. i> 

0E 

-Q OS 

h-5 


H o 
w ° 


•gjS 


CO 


Lbs. av. 
525.625 

let on. 
shut off. 


!d o3 

PQ 


cs 


Lbs. av. 
515.875 

Steam 
Steam 


1 


03 


■H 


. © iO 
gCO Orl(SCO^^O!Oi>lX)flSO 






CALORIMETRIC OBSEEVATIONS. 



101 



CALORIMETRY : QUALITY OF STEAM. 


ft 
l oc 

3a 


O 


p. 

* 00 

55 *> 

03 
,Q 
Hi 


g 


OS 


•3 

8 ^ 

GO 


P w 


00 


& °o 

bO CO 




P5 
ft 

ft 

O 

ft 
K 
fc) 

H 

pi 

ft 
Ph 

ft 
Eh 


03 to 

«1~ 


J> 


Deg. F. 

88.425° 

88.375° 

88.35° 

88.325° 

88.3° 

88.275° 


CD <* 

pq 


CO 


Deg. F. 

39.95° 

39.975° 

40° 

40.025° 

40.05° 




ft 

02 
ft 

i . 

w 02 

H 
94 

o 

ft 




»n 


hi a 


o5 
o 
a 

a 
cb 

>> 
pq 


«* 


> 
* w 

3° 


p? . 

ft P5 
Ph ^ 

So 

»g 

ft < 

°g 

H O 

M o 

2r 

ft 55 


is 

55« 


eo 


Lbs. av. 

526.875 

let on. 
shut off. 


li 

In 
PP 


en 


Lbs. av. 
517.375 

Steam 
Steam 


Eh 





- 


. -* w 

*! tH O r-l (Si CO •• tHh O «0 i> 00 OS © 
<] .. CO rH 
OS 






102 



TKIALS OF A WAKM-BLAST APPAKATUS. 











CALORIMETRY : QUALITY 


OF STEAM. 




















o* 


s 




d 










a • 
















c 


cr 


o 

o 








|1 




1 


£ 








1 




,3 










Hi 














■*! 




02 










t> s 




'O 










« b g 


Oi 


fi 


o 










o 


OS 








& H 




0) 










fc 




02 








^ 














<w 














53 














•Is 


H 












>^> 


H tf 












£ 


O £ 












i 


B 8 


00 




o 

lO 

00 






i 

'ci' 




fi 


5 








fi « 












a 
















Ph 

r-T 




1§ 

03 to 




fr 


o 
o lO 


o 

o ia o 


o 


OD 
QO 


Eh 


J> 


bb 


CO CD 


CO o io -^ 


tH 


£ 


a; M 




CD 


tH t-( 


rH tH t 


_l — 1 


tH 


§ 






fi 


os os 


OS OS OS OS 




I 














H 














(J 


& 














p 

1-3 


H 
■4 


si 

"SI 

<U OQ 

o W) 




a* 2o o ib 

^ Cv* lO J> o 


o 
lO 




i 






CO 


GO GO 00 OS 
b£ .... 

4> tH tH t-I H 


OS 






o 

M 






fi "* ^ TJH ^ 


-^ 






<1 




W^ 












>- 
















« 




tj • 












H 




i>W 












co 


fl 


£ o 




> *> 








M 


W 


& bo 




* js 








O 




r 2 


lO 


rfS 








q 


W 


1*1 




43 • 








§ 


P 


pqra 




fi OS 
























g 












§ 

fi 


Eh 
8 

2 


fi 




. co 








3 
1 


5 
£ 


>> 




vj OS 
fi OS 








i-^ 




M 












;— ( 














XI 
















X 


Eh W 
H Eh 

P 

O Q 

2s 


Is 

1- <n 


CO 


lO 

c3 CO 


■§' 








3 bfl 

<h3 




4= CO o 
fi <** Z. 

10 3 


^3 






















&3 


Hi 




3 


a 








's a 




• ~ * 


55 








Eh O 


nd =8 




> »C <D 


<u 










gfi 


e» 


S 5 * 


s 








oo 














o 






o 








S3 &,& 
Bc3S 

Eh -4 


- 


« "* O tH OJ CO tH 


CO 
• • «© t- CO 

iO 


• s ^ s 




H 
















« 
















CALORIMETEIC OBSERVATIONS. 



103 



CALORIMETRY : QUALITY OF STEAM. 


1 w 


o 


(f. OS 
Hi 


w o 5 


C5 


to 

1 © 

o oo 


n £ 

M &- ^ 
« O M 
^ ? 

fe Pi 

p | 


oo 


bb 

2 w 

ft o 


PS 
H 
H 

ft 
O 

PS 

& 

B 

-n 

PS 
W 

Ph 


la 

<3-M 


t- 


Deg. F. 

104° 

103.95° 

103. 925° 

103.9° 

103.875° 

103.8° 


la 

as a2 
pq 


CO 


Deg. F. 

41.5° 

41.525° 

41.55° 

41.575° 

41.6° 

41.625° 

41.65° 


ft 
W 
OQ 



sz; . 
w 

o 


u . 

i. o 

53 bD 

!.l 

pq^> 


m 


. OS 
> 00 

£ © 


03 
O 

G 

a? 
a> 

>> 

PQ 


TfH 


> W3 

03 

M i-t 


ps . 

a PS 

P5 ? 

gA 


11 

£ a 


eo 


Lbs. av. 
531.3125 

let on. 
shut off. 


(D 02 

pq 


c* 


Lbs. av. 
518.6875 

Steam 
Steam 




O 

O o 
< 

PS 


- 


SiOOT-iClCO'^JOOt-OOCiO'rH 

* id 



101 



TKIALS OF A WARM-BLAST APPARATUS. 



CALORIMETRY : QUALITY OF STEAM. 


CD • 

3 & 

i 00 
BQ 


o 


.3 

O 50 

Pi CO 

00 

i-5 




OS 


I B 


H O « 


00 


fe So 


H 

o 

■4 
K 
H 

H 


1§ 

O bJC 


I> 


fc S °o 

o o o 1C i> o 

to CD CD lO -^ "^ ^1 

A 05 CQ C"> C5 C5 C"> 

00 00 00 00 GO 00 


la 

QJ GO 


CO 


Deg. F. 

42.025° 

42.05° 

42.075° 

42.125° 


P 
H 

0Q 

w 

B 

O g 

&, w 
o 5 

H 

w 
g 




lO 


CO 


o 
a 

e 

>> 

PQ 


T* 


. CO 

3 i> 


« . 
««« 

SI 
SB 

f o 
W o 


11 

o> be 


co 


Lbs. av. 
526.1875 

let on. 
shut oft'. 


o> - .C 
« 


©» 


Lbs. av. 
518.25 

Steam 
Steam 


TIME 


OQ 



O P 

B 


- 


lO 






WATEK ENTEAINED IN STEAM. 



105 



Calculation of the quantity of entrained water in steam, from 
data obtained by calorimetric observations, Monday, July 11, 1881, 
lib. 43m. a.m. given in detail in Table XXIL (1), p. 91. 



Barometer, corrected reading 

Corresponding atmospheric pressure 

Boiler pressure by steam gauge 

Steam pressure absolute 

Number of British, thermal units above U F. con- 
tained in 1 lb. of saturated steam of 54. 53 lbs. per 
sq. in. absolute pressure 

Number of B. t. u. contained in 1 lb. of water of 
86.575° F. (also above 0° F.) 

Number of B. t. u. given up by 1 lb. of saturated 
steam of 54.53 lbs. per sq. in. absolute pressure 
condensed and cooled to 86.575° F 

Number of B. t. u. which would be given up by 
5.6094 lbs. of saturated steam of 54.53 lbs. per 
sq. in. absolute pressure, by condensation at 
86.575° ; 1114.6523 x 5.6094 = 

Gross weight of calorimeter and water therein con- 
tained, before admitting steam, col. 2 

Weight of calorimeter, empty 

Net weight of water in calorimeter 

Heat capacity of calorimeter, in equivalent weight 
of water. 

Calorific value in B. t. u. of calorimeter and contents 

Number of 13. t. u. contained in water at 86.575° ; 
brought forward 

Number of B. t. u. contained in water at 57.95 
(col. 4, p. 707.) 

Number of B. t. u. actuallv gained bv each 1 lb. of 
water raised from 57.95° F to 86.575° F 

Number of B. t. u. gained by 215.2 lbs of water, 
including the equivalent for the calorimeter, in 
rising from 57.95° to 86.575 ; 215.2 x 28.6662.. . 

Excess of the number of B. t. u. which would 
have been given up by saturated steam, over 
the number actually gained by the water, = 
6252.5306 - 6168.9662 

Ratio of this excess to the number which would 
have been given up by 5.6094 lbs. of saturated 
steam of 54.53 lbs. per sq in. absolute pressure, 
condensed at 86.575° F., = 83.5644 + 6252.5806 = 



in. 
. per sq. in. 

<< << 


29.79 
14.63 
39.90 
54.53 


B. t. u. 


1201.2755 


B. t. u. 


86.6232 


B. t. u. 


1114.6523 


B. t. u. 


6252.5306 


lbs. 
lbs. 
lbs. 


515.625 
317.625 

198. 


lbs. 
lbs. 


17.2 
215.2 


B. t. u. 


866232 


B. t. u. 


57.9570 


B. t. u. 


28.6662 


B. t. u. 


6168.9662 



B. t. u. 



Ratio. 



83.5644 



.013365 



It therefore appears that the 5.6094 lbs. of actual "steam " ad- 
mitted to the calorimeter was not saturated steam, but a mixture 
of saturated steam and water of equal temperature, in such propor- 
tions as to require 1.3365 per cent, of the quantity of heat which 
5.6094 lbs. of saturated steam of 54.53 lbs. per square inch press- 
ure absolute would have given in condensing at 86.575° F., to 
complete the evaporation of the entrained water. 



106 



TRIALS OF A WARM-BLAST APPARATUS. 



The temperature of the steam and water alike is. . 

The number of B. t. u. above 0° F. contained in 

water of temperature 286 3457° F. is 


Deg. F. 
B. t. u. 

B. t. u. 
B. t. u. 


286.3457 

288 5885 


From this number subtract the number of B. t, u. 
above 0° F. contained in water of temperature 
86.57.-)° F 

And we have the number of B. t. u. imparted per 
pound of water, between 286.3457° and 86.575° F. 


86.6232 
201.9653 



Each pound of saturated steam of 51.53 lbs. per square inch 
pressure absolute, and therefore of 286.3157° F. temperature, con- 
tains, as we have seen, 1201.2755 B. t. u., and in condensing and 
cooling to 86.575° F., must give out, 1201.2755 - 86.6232 = 
1114.6523 B. t. u., and 1114.6523 -^ 201.9653 = 5.5190, the ratio 
of the heating power of ' unit weight of steam to that of unit 
weight of water of this temperature. These two fluids, then, steam 
and water, are in this instance, mixed in such proportions that 
5.6094 pounds of the mixture give out, in cooling from 286.3457° 
to 86.575° F., 6168.9662 B. t. u. A few trials enable us to deter- 
mine that 98.365 per cent, of the 5.6094 pounds of the mixture, 
amounting to 5.5177 pounds, are steam, giving out : 



TABLE XXIII. 

QUANTITY OF HEAT LOST BY STEAM AND GAINED BY WATER. 



. 



5.5177 x 1114.6523 = 

And that 100 — 98.335 — 1.635 per cent., amounting: 

to 0.0917 pounds, are water, giving out 0.0917 

x 201.9653 = 

Making a total of 

Which, is substantially equal to the heat in B. t. u. 

gained by the water; 

= 215.2 x 28.6062 = 



B. t. u. 
B. t. u. 



B. t. u. 



6150.3170 



18.5202 
6168.8372 



6168.9662 



Calculations similar to the foregoing applied to the data obtained 
by ealorimetric observations at other times during the week, July 
11-16, as given in Table XXIL (1) to (14), give results which, 
with the one above given in detail, are tabulated below. 



BEDUCTION OF OBSEBVATIONS. 



10; 



TABLE XXIV. 

REDUCTION OF CALORI METRIC OBSERVATIONS. 



(1) 





Day in July, 1881, when 

experiments were made, and 

hour and minute of 

beginning of experiment. 


PRESSURES : ATMOS. AND STEAM. 


TEMPERATURES. 




Barometer. 


Steam gauge. 






NO. 


Day of 

month. 


Part of 
day. 


H. M. 


Inches 
of mer- 
cury, 
cor- 
rected 
to 32° 
F. 


Press- 
ure of 
atmos., 
lbs. per 
sq. in. 


Boiler 
press, 
above 
atmos., 
lbs. per 
sq. in. 


Boiler 
press, 
abso- 
lute, 
lbs. per 
sq. in. 


Of steam 
admitted to 
calorimeter 
and en- 
trained 
water, 
Degrees F. 


Of water 
condensed 

in calori- 
meter and 

entrained 

water, 
Degrees F. 


1 


2 


3 


4 


5 


6 


7 


8 


9 


10 


1 


11 


A.M. 


11:48 


29.79 


14.63 


39.9 


54.53 


286.3456 


86.575 


2 


11 


P.M. 


2:20 


29.80 


14.64 


75.5 


90.14 


320.1485 


98.55 


3 


12 


A.M. 


9:5 


29.69 


14.58 


54.2 


68.78 


301.5381 


94.4 


4 


12 


P.M. 


3:15 


29.63 


14.55 


75.5 


90.05 


320.0781 


102.625 


5 


13 


A.M. 


9:35 


29.52 


14.50 


17.5 


32.00 


253.9520 


71. 


6 


13 


P.M. 


3:5 


29.45 


14.46 


41.3 


55.76 


287.7748 


86.4 


7 


13 


P.M. 


5:15 


29.42 


14.45 


50.7 


65.15 


297.9286 


87.575 


8 


14 


A.M. 


9:30 


29.45 


14.46 


49.1 


63.56 


310.5596 


77.65 


9 


14 


P.M. 


3:45 


29.48 


14.48 


36.6 


51.08 


282.1972 


93.075 


10 


14 


P.M. 


5:30 


29.51 


14.49 


65.0 


79.49 


311.4098 


86.2 


11 


15 


A.M. 


9:10 


29.66 


14.57 


67.8 


82.37 


313.8312 


88.425 


12 


15 


P.M. 


1:40 


29.63 


14.55 


75.0 


89.55 


319.6835 


91.8 


13 


15 


P.M. 


5:55 


29.59 


14.53 


24.9 


39.43 


266.2530 


104. 


14 


16 


A.M. 


11:5 


29.30 


14.39 


33.4 


47.79 


278.0217 


82.6 




Mean 


s 




64.98 


296.4087 


89.3482 

















108 



TRIALS OP A WARM-BLAST APPARATUS. 



TABLE XXIV. — reduction of calorimetric observations. — Continued. (2) 





BRITISH THERMAL UNITS. 














Weight of 
water con- 
densed in 
steam-drum 
of calorimeter 
during experi- 
ment. 


Total B. t. u. which 




Contained in one 
pound of saturated 
steam of given abso- 
lute pressure 


Contained in 
one pound of 
water condens- 
ed in steam- 
drum of calori- 
meter. 


Which would have 
been imparted to the 
water if the steam 
had been saturated. 


would have been 

imparted to the 

water if the steam 

had been saturated, 

dry steam. 


No. 


B. t. u. per lb. 


B. t. u. per lb. 


B. t. u. per lb. 


Pounds av. 


Total B. t. u. 


1 


11 


12 


13 


14 


15 


1 


1201.2755 


86.6232 


1114.6523 


5.5324 

.0770 

5.6094 


6252.5306 


2 


1211.5858 


98.6257 


1112. £601 


8.6611 

.1182 

8.7793 


9771.0106 


3 


1205.9092 


94.4638 


1111.4454 


9.6603 

.0565 

9.7168 


10799.6927 


4 


1211.5637 


102.7129 


1108.8508 


12.5134 
.2190 

12.7324 


14118.3319 


5 


1191.3882 


71.0210 


1120.3672 


4.7630 

.0807 

4.8437 


5426.7226 


6 


1201.7115 


86.4478 


1115.2637 


6.7833 
.1151 

6.8984 


7693.5351 


7 


1204.8084 


87.6252 


1117.1832 


7.0696 

.0749 

7.1445 


7981.7154 


8 


1204.3102 


77.6813 


1126.6289 


7.6453 
.1359 

7.7812 


8766.5248 


9 


1200.0106 


93.1362 


1106.8694 


9.6207 
.0511 

9.6718 

9.7425 


10705.4195 


10 


1208.9076 


86.2474 


1122.6602 


9 '.7695 

9.3648 
.1312 

9.4980 


10967.8288 


11 


1209.6584 


88.4769 


1121.1815 


10646.7395 










9.7192 




12 


1211.4434 


91.8586 


1119.5848 


. 0425 

9.7617 

12.4828 
.1461 

12.6289 


10929.0509 


13 


11951463 


104.0920 


1091.0543 


13778.8156 










7.9065 




14 


1198.7372 


82.6402 


1116.0970 


7.9200 


8839.4882 


M 


eaii by weighing 
ean by difference 

ean apparent err< 






8.7681 
8.7366 

.0315 

8.66185 
.10625 


9762.6719 


M 








M 


>r 
















8.76S10 





EESULTS OF OBSEEVATIONS. 



109 



TABLE XXIV.— Continued. 

REDUCTION OF CALORIMETRIC OBSERVATIONS. (3) 





Weight of water 
in calorimeter 
including ther- 
mal equivalent 
of calorimeter. 


Temperature 
of water in 
calorimeter 
just before 
admitting 
steam. 


B. t. u. con- 
tained in one 
pound of water 
in calorimeter 
before admit- 
ting steam. 


B. t. u. impartec 
to one pound ol 
water raised 
from initial to 
final tempera- 
ture. 


Total heat gained 

by the water in 

column 16 in 

being raised from 

t in column 17 tc 

temperature in 

column 10. 


Deficit of heat 
due to water 
entrained in 
the steam. 
Difference of 
columns 15 
and 20. 


No. 


Lbs. av. 


Deg. F. 


B. t. u. 


B. t. u. 


Total B. t. u. 


B. t. u. 


1 


16 


17 


18 


19 


20 


21 


1 
2 
3 
4 
5 
6 
7 
8 
9 

10 
11 
12 
13 
14 


215.2 

216.6375 

216.6375 

216.1375 

218.3875 

217.075 

217.825 

217.2 

215.1375 

215.45 

216.95 

218.075 

218.2625 

217.825 

216.9143 


57.95 

54.1 

44.8875 

38.45 

46.575 

51.575 

51.35 

38 

43.625 

35.475 

40.05 

41.95 

41.65 

42.125 

44.84 


57.9570 
54.1051 
44.8895 
38.4505 
46.5770 
51.5790 
51.3540 
38.0000 
43.6266 
35.4750 
40.0510 
41 9510 
41.6510 
42.1260 
Means 


28.6662 
44.5206 
49.5743 
64.2624 
24.4440 
34.8688 
36.2712 
39.6813 
49.5096 
50.7724 
48.4259 
49.9076 
62.4410 
40.5142 
Means 


6168.9662 

9644.8315 

10739.6524 

13889.5145 

5338.2641 

7569.1448 

7900.7741 

8618.7784 

10651.3716 

10938.8709 

10505.9990 

10883.5999 

13628.5288 

8825.0056 

9664.5216 


83.5644 
126.1791 

60.0403 
228.8174 

88.4185 
124 3903 

80.9413 
147.7464 

54.0479 

28.9579 
140.7405 

45.4510 
150.2868 

14.4826 

98.1503 



110 



TEIALS OF A WARM-BLAST APPARATUS. 



TABLE XXIV.— Continued. 

REDUCTION OF CALORIMETRIC OBSERVATIONS. 



(4) 











BRITISH THERMAL 

UNITS. 


ratio: PER CENT. 




Day in July, 1881, when experiments 
were made, and hour and minute of begin- 
ning of experiments. 










Gained by 
the water in 
column 16, 
in being 
raised from 
initial to 
final tem- 
perature. 


Which 
would have 
been im- 
parted to 
the water if 
the steam 
had been 
saturated : 
dry. 


Heat re- 
quired to 
evaporate 
the en- 
trained 
water. 


Ratio of 

entrained 

water to 

total water 

and 

steam. 




Day of 
week. 


Part of 

day. 


Day of 
month. 


H. M. 




B. t. u. 


B. t. u. 


Per cent. 


Per cent. 


1 


22 


23 


24 


25 


26 


27 


28 


29 


1 


Monday 


A.M. 


11 


11:48 


6168.97 


6252.53 


1.34 


1.37 


2 


" 


P.M. 


11 


2:20 


9644.83 


9771.01 


1.29 


1.35 


3 


Tuesday 


A.M. 


12 


9:5 


10739.65 


10799.69 


.55 


.58 


4 


n 


P.M. 


12 


3:15 


13889.51 


14118.33 


1.62 


1.72 


5 


Wed'day 


A.M. 


13 


9:35 


5338.26 


5426.72 


1.63 


1.67 


6 


<< 


P.M. 


13 


3:5 


7569.14 


7693.54 


1.62 


1.67 


7 


w 


P.M. 


13 


5:15 


7900.77 


7981.72 


1.01 


1.05 


8 


Thursd'y 


A.M. 


14 


9:30 


8618.78 


8766.52 


1.69 


1.75 


9 


a 


P.M. 


14 


3:45 


10651.37 


10705.42 


.50 


.53 


10 


a 


P.M. 


14 


5:30 


1C938.87 


10967.83 


.26 


.28 


11 


Friday 


A.M. 


15 


9:10 


10506.00 


10646.74 


1.32 


1.38 


12 


it 


P.M. 


15 


1:40 


10883.60 


10929.05 


.42 


.44 


13 


<l 


P.M. 


15 


5:55 


13628.53 


13778.82 


1.09 


1.16 


14 


Saturday 1 
Meai 
Meai 


A.M. 
IS 

i ratios, pe 


16 


11:5 


8825.01 
9664.52 


8839.49 
9762.67 


.16 
1.04 


.17 
1.08 











POSSIBLE LIMITS OF ERROR. 



Ill 



A few words as to the possible limits of error in these observa- 
tions and results may be of interest. 



Mean weight of water, including 17.2 lbs. for calo- 
rimeter, col. 16 

Gross weight, after admitting steam 

Gross weight, before admitting steam 

Mean weight of steam, by difference 

Mean by separate weighing, col. 14 

Mean sum of errors 

Greatest possible error in separate weighing, gay 
7 grains 

Greatest probable error in weight of water in calo- 
rimeter 

Greatest probable error in pressure by steam gauge 
nnd barometer 

Greatest probable error in temperatures ; ther- 
mometers graduated to tenths of a degree F . . . 



lbs. 
lbs. 
lbs. 
lbs. 
lbs. 
lbs. 

lbs. 

lbs. 

lb. per sq. in. 

Deg. F. 



216.9143 

526.0759 

517.3393 

8.7366 

8.7681 

.0315 

.0010 

.0300 
0.1000 
0.1000 






In the following table, Table XXV., all the assumed errors are 
added to the mean in the left-hand column, headed "maximum" 
and subtracted in the right-hand column, headed " minimum," ex- 
cept in the third line, t 2 , temperature of water, final. The differ- 
ence, or assumed error is here subtracted in the left-hand column, 
and added in the right-hand column, since this tends to magnify 
the error in the final result. It will be noticed, that the mean deficit 
of heat, per cent., in this table — last line but one of middle column, 
is 1.16$, wmile in Table XXIV., it is 1.04$ — of course because the 
mean of the separate calculations ought not to agree with the re- 
sult of a calculation based on means of the observations. The wide 
variation from the mean — almost 40 per cent, each way — may 
occur in single observations, but are not probable, since errors are 
not unlikely to balance each other in some degree. In our case, 
with so many as fourteen observations, the mean result seems 
entitled to some degree of confidence. 

If the assumed errors in the third line are transposed, and the 
maximum be put into the left-hand column, as in all the other 
cases, the variation in the final result almost disappears — the three 
numbers in the line next to the bottom— deficit of heat, per cent., 
become respectively 1.15, 1.16, 1.17. There is no constant ratio be- 
tween the figures in column 28, Table XXIV., and those in column 
29, the latter being affected by variations of final water tempera- 
ture (column 10) and steam pressure and temperature (columns 8 
and 9). 



112 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE XXV. 
LIMITS OF ERROR IN CALORIMETRIC WORK. 






The numbers in this column, right-hand, 

refer to the headings of columns in 

Table XXIV. 



P, pressure absolute . 

t, temp, of steam 

t 2 , of water, final 

In 1 lb. of steam 

In 1 lb. of water 

Difference 

w, weight of steam 

Total heat 

W, weight of water 

t, of water, initial 

In water 

89.3017-44.9419, etc 

Total heat 

Deficit of heat 

Deficit of heat 

Water in steam 



8 
9 

10 
11 
12 
13 



14 

15 
16 
17 

18 
19 
20 
21 
28 
29 



KIND OF 
QUANTITY. 



Lbs.persq.in. 
Degrees F. 
Degrees F. 

B. t. u. 

B. t. u. 

B. t. u. 



Lbs. 

B. t. u. 

Lbs. 

Degrees F. 

B. t. u. 

B. t. u. 

B. t. u. 

B. t. u. 

Per cent. 

Per cent. 



MAXIMUM. 


MEAN. 


65.08 


64.98 


297.8587 


297.7565 


89.2482 


89.3482 


1204.7868 


1204.7558 


89.3017 


89.4018 


1115.4851 


1115.3540 




8.66185 




. 10625 


8.7691 


8.7681 


9781.8004 


9779.5354 


216.9443 


216.9143 


44.94 


44.84 


44.9419 


44.8417 


44.3598 


44.5601 


9623. 6058 


9665.7229 


158.1946 


113.8125 


1.617 


1.164 


1.683 


1.212 



64. 

297. 

89, 
1204 

89 
1115 



9777 

216 

44 

44 

44 

9707 

69 







6540 
4482 
7246 
5021 
2225 



7671 

2672 

8843 

74 

7415 

7606 

8714 

3958 

710 

739 









Continuous analysis of flue gases. — It would be out of place 
here to attempt a full description of the process of analysis pursued 
with the gaseous products of combustion, drawn from the descend- 
ing smoke-flue near the blower. Such a description would seem to 
a chemist impertinent, and to others than chemists, pedantic. In 
brief, it was the gravimetric process, and was conducted as follows : 

Samples of considerable volume were obtained through the 
mixing-box shown in Fig. 16, two of which were set in the flue, 






SAMPLING FLUE GASES. 



113 



one over the other, one foot apart, with the pipes disposed differ- 
ently, so as to bring long pipes over short ones, next to the longest 
over next to the shortest, and only the ends of the central pipe of 
each group of five over the ends of the corresponding pipes below 
them ; by which arrangement samples from the two boxes proved, 





cr C 

D 

HE 

Fig. 16. 

mixing-box, foil obtaining samples op flue 

gases for analysis. 

A., Section of flue. 

B, Section of mixing-box, showiDg tlie arrangement of 

the 25 pipes of \ inch gas-pipe. 
B', Front elevation of mixing-box. 

C, C, Pipes, four in number, from mixing-box to mixing 

chamber. 

D, Mixing chamber. 

E, Discharge-pipe leading to aspirator. 

by their agreement, that they truly represented the heterogeneous 
assemblage of unmixed gases passing through the flue. The greater 
part of the samples so drawn off by the aspirator was permitted to 
go to waste ; but a small stream w r as drawn out into a jar filled 
with glycerine, which flowed out in drops in regulated quantity, 
to be constantly replaced by the sample of gases. The small 
stream of gases so drawn off was divided, part going to each one 
8 



114 



TRIALS OF A WARM-BLAST APPARATUS 







ANALYSIS OF FLUE-GASES. 



115 



of two exactly similar sets of Geissler bulbs, first, however, 
passing through a bulbous tube, Fig. 18, which will arrest any 
liquid water condensed from vapor in the gases, and then through 
the U tube, also seen in the figure, which is filled with calcium 
chloride, and will (if kept at a low temperature, by surrounding it 
with crushed ice) take up all moisture, and leave the fixed gases 
completely dry. The dry gases next pass on to and through the 
group of three Geissler bulbs, each one filled about three-fourths 
full of hydrate of potash, i. <?., a saturated solution of caustic 
potash. At each drop of liquid, a small bubble of the mixed gases 
passes down through a central tube nearly to the bottom of the first 
bulb, and rises as a bubble through the hydrate of potash, to the 
space above the surface of the liquid, dismissing, simultaneously, a 
similar bubble at the bottom of the second bulb, which in turn, and 
simultaneously, dismisses a third bubble into the last bulb, and 
liberates a similar bubble to pass to and slowly through the second 
straight, horizontal, bulbous tube, seen at the left-hand of the Geiss- 
ler bulbs in Fig. 18. This bulbous tube is filled with dry caus- 
tic potash, which absorbs all moisture which may have been taken 
up by the dry gases in their passage through the hydrate of potash, 
so that the latter suffers no loss of weight — this bulbous tube and 
the set of Geissler bulbs being weighed together, as seen in Fig. 
17. The carbon dioxide (CO g ) contained in the mixed gases is 
taken up by the hydrate of potash, rapidly by that in the first bulb, 
which soon presents a nacreous appearance, more slowly by the 
second, which gradually becomes opalescent, and still more slowly 
by the third, which is very slightly affected, as nearly all the C0 3 
is absorbed in the first and second bulbs. 

Some water is taken up by the dry gases, and possibly a little 
C0 2 along with it ; but the dry caustic potash arrests both. The 
gases, deprived of their moisture and of their carbon dioxide, pass 
on to the left, to and through a glass tube about 0.6 inch in diameter 
and 20 inches long, seen about the middle of Fig. 18, extending 
through a small gas furnace. 

This tube has two porous plugs of fibrous asbestos, about six 
inches apart, near the middle of its length, and the space between 
these plugs is filled with copper scale (oxide of copper), which is 
kept at a low red heat by the gas furnace. The gases, which, it 
will be remembered, now consist solely of oxygen, nitrogen and car- 
bon monoxide (O, N, and CO), are changed, in passing through the 
hot copper scale, by the complete oxidation of the carbon in the 



116 



TRIALS OF A WARM-BLAST APPARATUS. 







ANALYSIS OF FLI3E-GASES. 117 



CO, and the conversion of the CO and additional oxygen into C0 3 . 
It is not easy — for a layman — to see just what office the copper scale 
performs that would not be as well performed by sand, or bits of 
fire-brick, since there is always an abundant supply of oxygen present 
in the surplus air. But the copper oxide would supply oxygen if 
there were none other present, and may act in some unexplained 
manner to promote oxidation of the CO. It is also possible that 
the dissociation of copper and oxygen offers less resistance than the 
mere mechanical obstruction of the nitrogen and carbon dioxide, 
after the free oxygen in the flue gases has been reduced as low as 
10 per cent. Some experiments cited by Angus Smith in Air and 
Bain, make this seem probable. An analogy is found in the case 
of iron, which burns eagerly in pure oxygen, but is rendered incom- 
bustible in common air, containing 21 per cent, of oxygen, by the 
mechanical obstruction of the 79 per cent, of nitrogen. However 
this may be, the carbon which enters the tube as carbon monoxide 
(CO), leaves it as carbon dioxide (C0 2 ). Passing on through a 
second set of potash bulbs, supplemented as before with a dry 
potash tube, this C0 2 is all absorbed, and the residuary gases, oxy- 
gen and nitrogen, are received in a bottle over water (or glycerine), 
and stored for measurement. 

This measurement is readily effected by weighing the liquid 
drawn off to make room for the gases. The weight and tempera- 
ture of this liquid (and its specific gravity, also, if other than water) 
being ascertained, its volume becomes known; the tension of the 
gases is made equal to that of the atmosphere, which is ascertained 
by the barometer; and their temperature being also noted, their 
weight becomes known. From the weight of these residuary 
gases, and that of the carbon dioxide and the carbon monoxide sep- 
arated from them, the weight of the original, dry, composite, or 
mixed gases is readily deducible. The absolute weight of the car- 
bon dioxide obtained, is found by directly weighing the potash 
bulbs and tube, as seen attached to the scale-beam in Fig. 17, before 
and after the experiment. The difference is the weight of the C0 2 
taken up by the potash, of which T 3 T is carbon and T 8 T oxygen. 

The weight of the carbon monoxide is ascertained, indirectly, in a 
similar manner. The difference in weight before and after the ex- 
periment is again C0 2 , of which all the carbon, T S T , and one-half 
the oxygen, T * T , are derived from the gases in the form of CO, and 
the remaining ^, oxygen, derived from the free oxygen in the 
surplus air, or from the copper oxide. 



118 TEIALS OF A WARM-BLAST APPARATUS. 

Sulphur, in burning, forms chiefly sulphurous acid (S0 2 ), and 
a small quantity of sulphuric acid (H 2 -f S0 3 = H 2 S0 4 ), both 
of which are taken up by the water. A small quantity of C0 2 is 
also absorbed by the water, bat this soon becomes saturated with 
C0 2 , while it will continue to absorb sulphuric acid and sulphurous 
acid for some time. It is better, however, to use glycerine. 

The quantity of II 2 S0 4 is so small as to render its accurate de- 
termination difficult in the flue gases, diluted as these are with air. 
The considerable increase in the quantity of ammonia found in the 
gases of the warm-blast boiler, makes it probable that all the sul- 
phuric acid exists as a sulphate, mainly sulphate of ammonia. 

Carbonate of ammonia was also produced in the warm-blast boiler 
in considerable quantities, coating all the smoke passages as white 
as the bolt- trough of a flouring mill. 

It is chiefly for the determination of the quantity of carbon diox- 
ide, of carbon monoxide and of surplus air, that analysis of the gas- 
eous products of combustion is desirable, and for those purposes it is 
invaluable. 

In addition to the continuous analysis, carried along all day and 
all night, in duplicate, for greater assurance of accuracy, samples of 
the gases drawn off at the same time were stored in bottles properly 
labeled, for subsequent repetition of the analysis in case verification 
appeared to be desirable. Such samples should be stored over gly- 
cerine, on account of the absorption of C0 3 by water; and on the 
same account the glycerine should be as nearly as possible anhy- 
drous. 

A very small steam or electric pump, with a plunger about 0.25 
inch diameter, and stroke 0.5, or 0.75 inches, driven at such speed 
as to give about one bubble of gas per second at each set of Geiss- 
ler bulbs, may be conveniently substituted for a siphon, to regulate 
the flow of the gases ; and a short bit of broken thermometer tube, 
of small caliber, inserted in the line of flexible tube, helps to give a 
more uniform flow. 

It is better to use Geissler bulbs of large size, and to deal with as 
large quantities of gas as can be conveniently managed ; and on this 
account the balance — which cannot be too nice — should be of large 
size, adapted to weigh, without undue strain, 200 grammes, nearly 
3,100 grains, say 7 oz. avoirdupois. With these precautions, proper 
care, adequate skill and perfect integrity, duplicate and repeated 
analyses will be found to agree very closely. Differences will ap- 
pear, under the high magnifying power of decimals of one per 






CABBON MONOXIDE. 



119 



cent., but these differences will usually be very small. Such quan- 
tities as 0.12, or 0.08 of one per cent. (.0012, or .0008), appear small ; 
but when they are found repeating themselves under like conditions, 
the results appear to be entitled to much confidence. Subsequent 
experience, indeed, has led Mr. Prentiss to the opinion that neglect 
to surround the calcium chloride tube with crushed ice may have 
permitted a little vapor of water to pass with the imperfectly desic- 
cated gases into the potash bulbs, and so to increase very slightly the 
small quantity of CO. Reference has already been made to persistent 
attempts to produce carbon monoxide in quantities unusually large 



CARBON-MONOXIDE PRODUCED BY EXCESSIVELY RAPID FIRING. 
GRAPHICAL REPRESENTATION OF TABLE XXVI. 
EXPERIMENTS MADE SEPT. I. 1881. 




A B.Cbal throw'n on the jgrates: CD. Coal Burned; s'caje, 400. lbs. per 
E F, Proportion of Carbon burned to CO: scale, 20 to-^' 
G H.Uss of heat by C 0| per cent scale, 29 to-,,, 
' J> Pounds of air per pound of c6al: scale; | ,20 Ibst pe r jj u 



and to special analyses of the chimney gases during short periods, at 
regular intervals, under certain conditions of the fire, to determine 
the quantity of CO so produced. Such experiments Were made dur- 
ing the entire working day, September 1, 1881. A succinct state- 
ment of the results of these experiments will be found in Table 
XXVL, and all the figures of this table, except those in columns 3 and 
4, are graphically represented on the diagram, Figure 19. Both table 
and diagram are so plain as to require little explanation. They 
will be readily understood by any one who will give them a few 
minutes careful attention. Beginning at the lower left-hand cor- 
ner of the diagram, it will be seen that a charge of 200 pounds of 



120 



TEIALS OF A WARM-BLAST APPARATUS. 



TABLE XXVI. 

CARBON MONOXIDE PKODUCED BY EXCESSIVELY BAPID FIRING. 



A.M. 
TIME. 


Pounds of 

coal thrown 

on the 

grate. 


Carbon 

dioxide in 

chimney 

gases. 


Carbon 

monoxide 

in chimney 

gases. 


Ratio of 

carbon in 

CO to total 

carbon. 


Pounds of 

air per 

pound of 

coal. 


Pounds of 

coal burned 

each half 

hour. 


Ratio of 
loss by CO 

to full 

power of 

coal. 


H. M. 


Lbs. 


Per centum, 

co 2 . 


Per centum, 
CO. 


Per centum. 


Lbs. 


Lbs. 


Per centum. 


1 


2 


3 


4 


5 


6 


7 


8 


6:15 


200 














6:45 


200 














7:15 


200 














7:45 


200 














8:15 


200 














8:45 


200 














9: 




5.12 


2.54 


43.80 


33.2 


83.81 


27.84 


9:15 


200 














9:80 




5.55 


2.89 


45.85 


29.5 


93.75 


29.14 


9:45 


200 














10: 




7.79 


3.99 


44.63 


21.4 


129.24 


28.37 


10:15 


200 














10:30 




7.70 


4.61 


48.47 


20.1 


187.60 


80.81 


10:45 


200 














11: 




7.82 


4.70 


48.57 


19.8 


139.68 


30.88 


11:15 


200 














11:30 




8.01 


4.81 


48.55 


19.3 


143.30 


30.86 


12 M. 










19.3 


143.30 




12:30 




15.21 


.25 


2.53 


19.3 


143.30 


1.60 


12:45 


200 














1: 










20.05 


137.94 




1:30 




14.11 


.21 


2.28 


20.8 


132.96 


1.49 


2: 










21.05 


137.94 




2:30 




13.62 


.33 


3.67 


21.3 


129.85 


2.31 


2:45 


200 














3: 




14.50 


.48 


4.95 


19.4 


142.56 


3.14 


3:30 




13 18 


.29 


3.34 


22. 


125.34 


2.12 


3:45 


200 














4: 




14.96 


.38 


3.84 


19.3 


143.30 


2.44 


4:30 




14.18 


.41 


4.35 


20.3 


136.25 


2.76 


4:45 


200 














5: 




13.01 


.41 


4.72 


22. 


125.34 


3.00 


Mean quantity of air. 






21.653 






Mean of all but two f3 


rst 




20.36 






Mean ratio of loss ; fi 

]yf*mn rat.in r»f lr»«s • Is 


rst 6, per < 
st 8, per c 


ICYlt 


29.65 


ent 






2.36 






"* *~~~ . ..- 











coa l — anthracite, egg size — was thrown on the fire-grates, upon a 
banked fire, started up at 6:15 a.m., and a like charge every 30 
minutes thereafter until 11:15 a.m. 

After an interval of 1 hour and 30 minutes, at 12:45 p.m., 200 



CARBON MONOXIDE. 121 

pounds was again thrown on the fire ; and again at 2:45, 3:45, and 4:45 
at intervals, respectively, of 2 hours, 1 hour and 1 hour. Thus, the 
firing was, for 5 hours 15 minutes, up to 11:15 a.m., at the uniform 
rate of 400 pounds per hour, equal to 16 pounds per square foot of 
fire-grate per hour; and after 11:15 a.m., it was at the mean rate of 
145.45 pounds per hour, equal to 5.82 pounds per square foot of 
fire-grate per hour — only 36 per cent, as much. 

Beginning at 9 a.m., samples of gas were obtained and analyzed 
half-hourly, except at the hours of 12 m., and 1 and 2 p.m., when 
there was, in each case, an interval of an hour. The half-hourly sam- 
ples were taken during the whole preceding half hour, and the hourly 
samples during the whole preceding hour, so that the whole day from 
half -past eight is covered by the analyses of the gases. The ratio, 
per cent, of C0 2 and of CO to the total quantity of dry flue gases, 
is given in columns 3 and 4 of Table XXVI., but these figures are 
not represented on the diagram, Fig. 19. 

In column 5 of the table, represented by line EF of the diagram, 
the proportion of coal burned to CO is given as a per centum of all 
the carbon in the coal. During 2 hours and 30 minutes, 9:00 to 
11:30 a.m., the mean is 46.64 per cent., showing that only 53.36 per 
cent, was completely burned to C0 3 . The number of pounds of 
atmospheric air found in the flue gases for each pound of coal con- 
sumed, given in column 6 of the table, and represented by line I J 
of the diagram, was rather small, and nearly uniform ; the mean 
for 8 hours being 21.65 pounds, and for 7 hours, after 10:00 a.m., 
only 20.36 pounds. The ratio of heat lost by CO to the full heat- 
ing power of the coal is given in column 8 of the table, and is 
represented byline GH of the diagram. 

This loss is obviously less than the whole quantity of CO pro- 
duced, because some heat is evolved in burning carbon to CO. 

While carbon burned to C0 2 produces, per pound, 14,544 Brit- 
ish thermal units, the same quantity burned to CO produces but 
4,451 of the same heat units. The loss (= 14544 - 4451 = 10093 
British thermal units) is about 69.39 per cent., and the numbers in 
column 8 would be 69.39 per cent, of those opposite in column 5, if 
carbon were the only combustible in the coal, as it is in coke. But 
there is, in fact, an appreciable quantity of hydrogen in this coal, 
probably united with carbon as some one or more of the hydrocar- 
bons, useful as fuel, and this hydrogen losesnothing in consequence 
of the formation of CO ; and the effect of this circumstance is to 
reduce the ratio of the loss by CO to about 63.5 per cent. 






122 TKIALS OF A WAEM-BLAST APPAEATUS. 



The losses to be accounted for, to be guarded against, and to be re- 
duced to a minimum, in the combustion of coal in the furnaces of 
steam boilers {aside from external radiation from boiler and brick- 
work), are all embraced as classified under the five heads, B, C, D, 
J5*and F, in the following list. 

A — Pounds off flue gases per pound of coal. 

A — a = Pounds of atmospheric air per pound of coal. 

B = Heat carried off by flue gases (exclusive of vapor contained 
in these gases). 

C = Heat lost by water in the coal. 

D = Heat lost by vapor in the air. 

E = Heat lost by CO in the flue gases. 

F = Heat lost by hydrogen in the flue gases. 

a = Number of pounds of carbon in 100 pounds of coal. 

b ~ Number of pounds of hydrogen in 100 pounds of coal, 

c = Number of pounds of water in 100 pounds of coal. 

d = Number of pounds of ash in 100 pounds of coal. 

e = Number of pounds of C0 2 in 100 pounds of flue gases. 
f = Number of pounds of CO in 100 pounds of flue gases. 

g — Number of pounds of hydrogen in 100 pounds of flue- 
gases. 

h = Proportion of vapor in atmospheric air. 

k = Number of British thermal units developed by 1 pound of 
coal perfectly burned; ascertained by analysis. 

n = Temperature of external air; degrees F. 

p = Temperature of escaping gases ; in smoke-box, with natural 
draft, or in blower, with the warm-blast apparatus. 

To compute the number of pounds of dry flue gases, per pound 
of coal consumed : 

A a 

~ .27273* + .42857/ & 

That is : — Divide the number of pounds of carbon found by an- 
alysis in 100 pounds of coal (a), by the sum of T \ = .27273 of the 
C0 2 , and f = .42857 of the CO, found by analysis in the flue gases. 
The quotient will be the number of pounds of dry flue gases per 
pound of coal consumed. 

EXAMPLE. 

We find, for instance, that during the week I, ending May 20, 
1882, the mean number of pounds of C0 2 in 100 pounds of flue 



LOSSES ATTENDING COMBUSTION. 123 

gases (days), was 12.27 ; and of CO, 0.18 pounds ; and that the 
number of pounds of carbon in 100 pounds of coal was 82.92. 

Then, L^JM 7 = 3.342727 

and 3 X ,°- 18 = 0.077143 



.272736? + .42857/ = 3.419870 

82.92 
and ^^^ = 24.2 = A. 

A - a = 24.2 - .8292 = 23.37 = the number of pounds of 
atmospheric air in flue gases per pound of coal consumed. 

To find the heat carried off by the flue gases (exclusive of vapor 
contained in these gases), in terms of the full heating power of the 
coal. 

B ^ A x .238 x (p-n) 

That is, multiply the number of pounds of flue gases per pound 
of coal consumed, by .238. which is the mean specific heat of tbe 
mixed flue gases; and this product by the difference in tempera- 
ture in degrees Fahrenheit between the external air and the escap- 
ing gases — at the smoke-box, with natural draft, or, at the blower, 
with the warm-blast apparatus; and divide this second product by 
the number of British thermal units expressing the full heating 
power of the coal. 

EXAMPLE. 

A = 24.2;^- 164°; n = 49° ; p - n = 115°; & = 13139. 

Then : , tj— = .0504 = B = 5.04<1 

To find the heat lost by water in the coal, in terms of the full heat- 
ing power of the coal. 

rf _(c + %) x (1076 - n + .48;;) . 

6 ~ wok {o} 

That is, to the number of pounds of water in 100 pounds of coal, 
add 9 times the number of pounds of hydrogen in 100 pounds of 
coal, and multiply the sum by the number 1076 diminished by the 



124 TRIALS OF A WARM-BLAST APPARATUS. 

number of degrees F. expressing the temperature of the external 
air, and increased by 0.48 times the number of degrees F. expressing 
the temperature of the escaping flue gases — at the smoke-box, with 
natural draft, or at the blower, with the warm-blast apparatus; and 
divide the product by 100 times the number of British thermal 
units expressing the full heating power of the coal. 

The quotient will be the loss by water in the coal, the quantity 
sought. 

EXAMPLE. 

Let c = 2.39 ; b = 1.80 ; n = 49° F. ; p = 164° ; 0.48 = spe- 
cific heat of steam ; .48^? = 79, and 100& = 1313900. Then : 

r _ [2.39 + (9 x 1.80)] = 18.59 x (1076 - 49 + 79 = 1106) _ 

~ 1313900 

.0156 = 1.56*. 

To find the loss of heat by vapor in the air, in terms of the full 
heating power of the coal expressed in British thermal units: 

D = (A-Tfa) x hx A8(p-n ) 

That is, from the number of pounds of flue gases per pound of 
coal consumed, subtract one one-hundredth part of the number of 
pounds of carbon in 100 pounds of coal ; and multiply this differ- 
ence by the proportion of vapor in the air as ascertained by the 
hygrometer, and by 0.48 times the difference between the number 
of degrees F. expressing the temperature of the escaping flue gases 
(at smoke-box, or blower, as the case may be), and the number of 
degrees F. expressing the temperature of the external air ; then 
divide the continued product by the number of British thermal units 
expressing the full heating power of the coal. The quotient will 
be the loss of heat by vapor in the air, in terms of the full heating 
power of the coal. 

EXAMPLE. 

Let A = 24.2 ; a = 82.92 .-. T fo = .8292 ; h = 1.80* ; p = 164°, 
n = 49°, p - n = 115° F. and k = 13139. Then : 

D = (24.2 - .8292) x .018 x .48 x 115 = mg = Q ^ 

Lo Lou 



LOSSES ATTENDING COMBUSTION. 125 

To find the heat lost by carbon monoxide in the flue gases, in 
terms of the full heating power of the coal expressed in .British 
thermal units. 

If x 101a _ .42857/ x 101a _ 

^ - ( T 3_£ + sy) x fc ~ (.27273* + .42857/) x k' } 

That is, multiply three-sevenths (f = .42857) of the number of 
pounds of CO found by analysis in 100 pounds of flue gases, by 
101* times the number of pounds of carbon found by analysis in 
100 pounds of coal ; and divide this product by the continued 
product of the number of British thermal units expressing the full 
heating power of the coal, multiplied by three-elevenths of the 
CO 2 and by three-sevenths of the CO, in pounds found by analysis 
in 100 pounds of flue gases. The quotient will be the loss of heat 
caused by the CO in the flue gases, in terms of the full heating 
power of the coal expressed in British thermal units. 

EXAMPLE. 

Let/ = 0.180 ; a = 82.920 ; e = 12.270, and h = 13139. Then : 

(| x .18) x (82.92 x 101) _ = 

~ [( f \ x 12.27) + (f x .18)] x 13139 * ' 7 * 

To find the heat lost by hydrogen in the flue gases, in terms of the 
full heating power of the coal, expressed in British thermal units. 

p- Axax 620.32 (Q) 

That is, multiply the number of pounds of flue gases per pound 
of coal consumed by the number of pounds of hydrogen found by 
analysis in 100 pounds of flue gases, and by 620.32 ( = one one- 
hundredth part of the number of B. t. u. expressing the full heating 
power of one pound of hydrogen) ; and divide the product by the 
number of British thermal units expressing the full heating power 
of one pound of the coal as determined by analysis. The quotient 
will be the loss by unburned hydrogen in the flue gases, in terms 
of the full heating power of the coal, expressed in British thermal 
units. 

*101, put for 1 -?^ = 100.93 ; the sum 10093 being 14544 - 4451, see p. 121. 



126 TRIALS OF A WAEM-BLAST APPARATUS. 

EXAMPLE. 

Let A = 24.2 ; g = ; k = 13139. Then, 

„ 242 x x 620.32 n 
F= 13139 = °- 

~No hydrogen lias ever been detected in the fine gases, and it 
seems little likely that any ever escapes from the furnace unburned. 
Some hydrocarbons, in natural gas, deposit a portion of their car- 
bon in a solid mass behind the bridge wall, especially if introduced 
into the furnace at too high a temperature ; but it is probable that 
all the free hydrogen present, and all which is combined with car- 
bon, that is, all that is not already burned to water, is so burned in 
any furnace fire. If, however, any hydrogen should ever be found 
in the flue gases, its quantity inserted in place of in the above 
example, will bring out the resulting loss of heat. The sum of the 
losses B, C, D and E, is as follows : 

B, loss of beat carried off by tbe dry flue gases 5.04 

C, loss of beat by water in coal 1.55 

D, loss of beat by vapor in tbe air 0.18 

E, loss of beat by carbon monoxide 1.44 

Total losses at tbe chimney, per cent 8.21 

Add to this tbe loss by radiation from boiler and brick -work ; a 
quantity varying with tbe temperature of tbe external air and 
with tbe conditions of each case, but in this case 4.00 

Total sum of losses, per cent 12 21 

Efficiency of boiler, per cent 87. 79 

100.00 

Various small savings can be made in ways already pointed out, 
which, in the aggregate, may be brought up to the 2.21 percent, re- 
quired in order to make the net efficiency 90 per cent. There is still 
five per cent, of the heat carried off by the flue gases at the moderate 
temperature of 164° F., only 115° F. above the temperature of the 
external air. 

Part of this may sometimes be saved by warming water after 
the gases leave the abstractor, and possibly a little may be saved 
by improvements in the abstractor itself. 

But according to present appearances 90 per cent, is about the 
maximum efficiency attainable by the best possible boiler with 
warm-blast apparatus, and that should be steadily aimed at and 
pretty nearly attained. 

Ashes and Kesidtje. — All ashes and residue withdrawn from 












ASHES AND KESIDUE. 



127 



the furnace and ash-pit during each weekly experiment were kept 
together under cover, until the fire was drawn at the end of the 
week's work, at midday on Saturday. The fire was allowed to 
burn pretty low on Saturday : still, as steam was kept up, there 
was some partially burned coal on the grates when the fire was 
drawn, and some water was used to quench this coal ; but only 
enough to cool it by evaporation below the point of ignition, so 
that the ashes and residue, when cold, might be considered to be 
as dry as the hygrometric state of the air would permit. After 
division, as has been already said, into five grades, namely (a), 
unburned coal (a small quantity) ; (b), clinker, partly vitreous ; (c), 
coarse residue, which would not pass through a screen with hexag- 
onal meshes five-eighths of an inch in short diameter ; (d), finer 
residue, passing through said hexagonal meshes, but not passing 
through a screen with three meshes to an inch each way ; and (e), 
ashes which passed through said screen ; each grade was weighed 
by itself, kept separate, and sampled for 
analysis. The first grade (a) was pulver- 
ized and sampled in the same manner as 
the week's coal. The second grade (&), 
clinker, was sampled, by taking a part 
of almost every lump, making as fair a 
selection as possible. This grade, which 
sometimes reached 500 pounds in a week 
— more than one-fifth of the whole quan- 
tity of ashes and residue — was nearly 
barren of carbon, while the first grade, 
although small in quantity, was little in- 
ferior in carbon to fresh coal. 

The third grade (c), the fourth grade 
(d), and the fifth grade (e), were sampled 
by passing them twice in succession 
through an ore-sampler, shown in Fig. 
20. Placed in the conical hopper A, 

,i -i ,i 1 i / \ ORE SAMPLER, FOR OBTAINING 

tiiey passed tiiougn its open end (a), con- samples of ashes and residue. 
centrically upon the apex of the right cone FlG - 30 - 

B, which distributed them evenly on all sides in a sheet, growing 
gradually thinner toward its base, near which were placed four 
tubes, one inch in inside diameter, equidistant in a circle forty 
inches in circumference, so that each tube was equal in diameter 
to one-tenth of the quadrant in which it was set. 




HORIZONTAL SECTION 



128 TRIALS OF A WARM-BLAST APPARATUS. 






Of each tube, the side facing the center of the cone and above 
its surface, was cut away so as to present an open mouth, one inch 
wide, towards the descending sheet of ashes or cinders, one-tenth 
of which they received and conducted into the quadrant-shaped 
cups beneath them in the base of the sampler. 

When these cups were full, or when all the ashes or cinders of 
any grade had been passed through the sampler, the cups were 
taken out, emptied, and replaced in position : and their contents 
were again passed through the sampler. By this process, supple- 
mented by a small correction (found by weighing the whole quan- 
tity, and the quantity delivered each time into the cups), for any 
variation in the actual dimensions of the sampler from the exact 
one-tenth contemplated, a known proportion, about one one-hun- 
dreth part of each grade of ash and cinders was obtained, of pre- 
sumably average quality. Each sample so obtained was then pul- 
verized, and a smaller sample obtained by subdivision in the man- 
ner usual in treating ores, was finally bottled, labeled, and put aside 
for analysis in its turn. The fifth grade (<?) was, after sampling, 
again subdivided by passing its finer portion through a sieve of 
brass wire-cloth of forty meshes to an inch each way. The portion 
which passed through this sieve, which was much the larger por- 
tion, was almost wholly incombustible ash — only about 5 per cent, 
of it being carbon, while the portion remaining on the sieve, 
although small in quantity, was almost wholly pure coal, appa- 
rently resulting from decrepitation. The weight of each grade 
being known, and the proportion of carbon in each being ascer- 
tained by analysis, it of course follows that the total quantity of 
carbon in ashes and residue becomes known. 

It is probably a safe assumption that no combustible save carbon 
remains, since volatile hydrocarbons must be either burned to 
C0 2 and water, or driven off' by the heat of the lire. 

Results finally obtained in the manner above described may be 
checked by a method much easier, and little less accurate, even in 
theory, while its simplicity eliminates an accumulation of errors of 
observation, and makes it, in practice, quite as accurate. 

This second method is as follows : 

The analysis of the coal thrown on the fire-grates during the 
week gives the proportion of ash it contains, and this proportion 
applied to the weight of the coal consumed during the week, after 
deducting the weight of the nn burned coal picked out of the ashes 
and residue [grade (a)], gives the quantity of "ash" proper, in the 



STEAM PKESSUEE IN BOILEK. 



129 



week's ashes, cinders, and clinkers of all grades (&), (>), (d), and (e). 
It follows that the excess of tlie combined weight of ashes and resi- 
due of these four grades, over the weight of ash as determined by 
analysis of the coal, is equal, or nearly equal to the quantity of car- 
bon contained in the ashes and residue of these four grades. It 
would be exactly equal if all the un burned coal could be picked 
out; but this can hardly ever be the case, since no inconsiderable 
quantity goes through the grates in particles too fine to be picked 
out, and can be segregated only by subdividing grade (e), after pul- 
verization, by means of a line sieve, as above described. In treat- 
ing a coal which decrepitates very badly, it may be necessary to 
sample and analyze the ashes and residue, as herein described. 
Such is the Rhode Island coal, large lumps of which sometimes 
crumble to fine black sand and sift through a thick lire to the ash- 
pit, with startling suddenness, without becoming too hot to be held 
in the hand. But in the use of most, perhaps all, of the Pennsyl- 
vania anthracites, the second and simpler mode of procedure I have 
described will be found sufficiently accurate ; and this was the 
method pursued in the later portion of our work. 

Boiler Pressure by Steam Gauge. — One of Edson's Pressure 
Recording Gauges was connected with the boiler, and kept in op- 
eration throughout the whole duration of the trials. A set of the 
diagrams from this gauge running through the days and nights of 
the week ending July 23, 1881 (week B), is given in Fig. 21a, 



PAC 


IFIC BO 


LER 






July 


18. Day.. 












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Nvf l 






V 


ly 


VtV 





















































6 7 8 

PACIFIC BOILER 



11 12 M. 1 

July 18-19. Night. 











































































-S- 






-+-H— 






i i i 


i i-t— 


-H-J- 






i i ■' 


(Y 






nil 






— m 






i i i 


"III 













































































? 



8 9 10 11 12 P.M. 12 3 4 

"Week"B, Ending July 23. 1SS1, Edson's Pressure Recording Gauge 

Fig. 21a. 
9 



20 



130 






TKIALS OF A WAKM-BLAST APPARATUS. 



h, c, d, e, and/, reduced by photography to two-thirds of the size 
of the diagrams. The upper diagram on each set exhibits the 
pressures during the day— 6 a.m. to 6 p.m., except on Saturday, 
when the day closed at 12 m. They show very clearly the ex- 
tremely unequal demand for steam, but very inadequately, for two 
reasons '.—first, because the fire was urged and evaporation was ac- 
celerated whenever steam pressure was rapidly drawn down, and in 



PACIFIC BOILER 



July 19. Day. 



/IY 
























s 


A, 






















'V, 


J Vr 


v. 
















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6 7 8 9 10 11 12 M. 1 2 

PACIFIC BOILER July 20-21. Night. 



±=fc 



^ 



6 7 8 9 10 11 12 P.M. 12 3 4 

Week B, Ending July 23. 1S81 Edson's Pressure Recording Gauge 

Fig. 21c. 



20 



7 8 9 10 11 12 M. 1 2 3 4 5 

PACIFIC BOILER July 19-2". Night 









j_ 1 4— 






























— (— H - 


1 1 1 


— |-^r — 






























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7 8 9 10 11 12 P.M. 12 3 4 

Week B, Ending July 23. 18S1. Edson's Pressure Recording Gauge 

Fig. 216. 



4 5 





PACIFIC BOILER 






July 20. Day. 




















rr- 


-+-. 


















00 
40 

20 





A 


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PACIFIC BOILER 


DIAGRAMS 


OF STEAM 

July 21. Day. 


PRESSURE 


















^X ^ 


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131 



6 7 8 9 10 

PACIFIC BOILER 



11 12 M. 1 2 

July 21-22. Night. 



T-H I - 1 I l «' = ^~i \- J -r-l 



8 9 10 11 12 P.M.. 1 .2 3 4 

Week'B, Ending July 23. 1881. Edson's Pressure Recording Gauge 

Fig. 21d. 



8 9 10 11 12P.M. 12 3 4 

Week B, Ending July 23. 1881. Edson's Pressure Recording Gauge 



PACIFIC BOILER 



Fig. 2U 



Saturday, July 23. 188i:Day. 



m 



* 



s 




Kpl 



7 8 9 10 11 12 M. 1 2 3 4 

Week B, Ending July 23. 1SS1. Edson's Pressure Recording Gauge 



PACIFIC BOILER 






July 22. 1881 Day 










/^S 
























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C 7 8 9 10 11 12 M. 1 2 3 4 5 6 
PACIFIC BOILER July 22-23. Night. 


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Fig. 21/. 



132 TEIALS OF A WARM-BLAST APPARATUS. 






some degree checked when it rose ; and second, on account of the 
smaller scale on which this gauge records pressures in the upper 
portion of its register, the 10 lbs., 70 to 80, occupying only half as 
much space as the lower 10 lbs., above 0. The effect of this is to 
mask the irregularities, in some degree, making them appear much 
less than if the scale were uniform throughout. 

The Edson gauge is excellent for the purpose of recording the 
general state of the pressure ; but its indications are not sufficiently 
accurate for numerical calculation, if for no other reason, on ac- 
count of the small scale on which it works. 

It was therefore necessary to take readings of an accurate press- 
ure gauge at stated intervals, as accurately spaced in time as pos- 
sible. 

Such readings were taken every quarter of an hour during the 
day, and part of the time by night also ; but the greater uniform- 
ity at night led us, soon, to take readings at the hours and half- 
hours only. The gauge was a ten-inch Bourdon test gauge, made 
by the American Steam Gauge Company, which had never before 
been used except for comparison with other gauges. It had been 
compared many times with a mercury column, with which it 
agreed quite closely, and had not been used after having been so 
tested, until it was used in these experiments. 

It was connected with the boiler by a branch pipe from the pipe 
leading to the Edson gauge, and as the pressure was shut off from 
the test gauge except when a reading was to be taken for record, 
a slight reduction of pressure took place at the Edson gauge when- 
ever the stop-cock of the test gauge was opened, producing by the 
downward motion of the marking pencil, and a little recoil on its 
rising at the close, a short mark crossing the trace of the Edson re- 
cording gauge, which indicates the moment of the reading, and the 
point in the trace with which the reading is to be compared. A 
mean was taken of the readings of the test gauge for each day, and 
for each night, and a general mean for each week, of the days and 
also of the nights. It will be observed that the diagrams, Fig. 180 
a, b, etc., are reversed in direction from the original diagrams, 
which read from right to left. This is merely for convenience of 
reading in the ordinary manner, from left to right. I have not 
thought it worth while to reproduce here these diagrams for more 
than a single week, since these fairly represent them all in general 
character. 






CAPACITY OF BOILEK. 133 

Capacity of Boiler at various heights of water llne and at 
various pressures. — A scale, graduated to inches and tenths of an 
inch, was attached to each glass water gauge in such a manner that 
the surface of the water in the glass tube could be readily referred 
to it, and readings of this gauge were recorded every quarter of an 
hour. It was practically impossible to maintain a uniform water 
level, and it was found to be inconvenient to bring the water at 
the close of an experiment, at noon on Saturday, to agree exactly 
with that at starting, on Monday morning. It was therefore neces- 
sary to ascertain the true difference in quantity due to any observed 
difference in height of surface ; and convenience required that this 
should be ascertainable by inspection of a table. The subjoined 
table, Table XXVIL, was therefore constructed, showing the ca- 
pacity of the boiler expressed in pounds avoirdupois of water at 
the zero of the scale, and at each inch of height above that zero, 
with differences for ascertaining by interpolation the quantity for 
parts of inches. The height, in inches of the water surface above 
the zero of the scale, is given in the left-hand column of the table, 
which is in two parts. But the weight of a given volume of water 
varies with its temperature, which corresponds with the absolute 
steam pressure. The table is, therefore, computed for 17 different 
pressures, from =■ one atmosphere = 14. 7 pounds per square inch 
absolute, up to 80 pounds steam-gauge pressure = 94.7 pounds ab- 
solute, at intervals of 5 pounds, as indicated by the figures at the 
head of the columns, which are steam-gauge pressures; with col- 
nms of differences for ascertaining by interpolation the quantity of 
water at intermediate pressures. The zero of the scale is near the 
lower end of the tube, and about 3.08 inches above the top of the 
upper row of flues, and 9.33 inches above the center of the shell. 

EXAMPLE OF THE USE OF THE TABLE. 

In the experiment for the week ending May 20, 1882, at 6 h. 
32 m. a.m. on Monday, May 15, the reading at the scale of the glass 
water gauge was 5.3 inches; pressure of steam by steam gauge, 15 
pounds. At 12 m. on Saturday, May 20, water stood at 3.0 inches, 
steam at 50 pounds. 






134 TKIALS OF A WARM-BLAST APPARATUS. 

Then, by consulting the table, we find in the column 
headed 15, opposite the height of 5 inches, water in 

boiler 13,546 lbs. 

Difference for 1 inch = 424 lbs. 

And 424 x .3 = 127 lbs. 

Pounds of water at starting 13,673 lbs. 

The column headed 50, opposite the height 3 inches, 

water in boiler 12,404 lbs. 

Number of pounds less at the end of the experiment than 

at its beginning 1,269 lbs. 

Number of pounds fed into the boiler during the experi- 
ment 156,214 lbs. 

Number of pounds of water evaporated during the ex- 
periment 157,483 lbs. 

Since the two boilers are alike, this table applies equally well to 
both. 

Radiation from Beiok-woek. — An attempt was made to meas- 
ure the quantity of Jieat lost by radiation from the brick-work, 
which, although unsatisfactory, yet seems to possess some interest, 
and will be briefly noticed. 

The Appaeattjs. — Two tin-plate vessels were provided, each 
twelve inches square and one inch thick, closed on all sides. On 
one side, near the corners, there were two rings by which the ves- 
sels could be hung up upon nails driven into the brick- work. In 
the upper edge, when so suspended, there was a tubular orifice, 
about 0.75 inch in diameter, slightly tapering, for convenient in- 
sertion of a cork. Through the cork two small glass tubes were 
inserted ; one, for inflowing water, extending down inside nearly to 
the bottom of the vessel ; the other, for outflowing water, extend- 
ing but slightly through the cork. 

Each of these tubes, near the entrance through the cork into 
the vessel, was provided with a suitable enlargement, bend and 
orifice for convenient insertion of a thermometer, to show the tem- 
perature of inflowing and outflowing water. Water was supplied 
from a bucket suspended in an elevated position, and received in a 
bucket on the floor, surrounded by ice, to reduce loss of weight by 
evaporation. The edges and the back of the vessels were protected 
from loss of heat by radiation, at least in some degree, by a hood of 
cotton flannel filled with eider down ; and the edges of this hood 
were drawn slightly over the naked side next the brick-work, by a 
gathering-string, to cut off circulating air currents which would 
carry off heat by convection. Finally, the naked side was coated 
thickly with dry lampblack, for the better absorption of radiant heat. 



CAPACITY OF BOILEE. 



135 



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t-I 






RADIATION FROM BKICK-WOKK. 



137 



The method of using this simple apparatus consisted of noting 
at frequent and regular intervals the temperature of the inflowing 
and outflowing water, and in ascertaining the quantity of water 
flowing through each vessel in a known interval of time, 

Trial of the Apparatus. — On the 10th of August, 1881. both 
these radiometers were placed, side by side, on the smoke-box cover 
of the Pacific Boiler — marked, for distinction No. 1 and No. 2 — 
and streams of water, supposed to be nearly alike, were set to flow 
through them. A first experiment of one hour, 8 h. 45 m. to 9h. 45 m. 
a.m., was immediately followed by a second, of 3 h. 30 m. — 10 h. m. 
a.m. to 1 h. 30 m. p.m. Observations of temperatures were noted 
every 15 minutes. The water was weighed at the close of each ex- 
periment. The results are given in Tables XXVIIL and XXIX. 

The line marked " B. t. u., total," is obtained by multiplying the 
number of British thermal units corresponding to the increase of 
temperature, by the number of pounds of water to which such 
quantity of heat w T as imparted, in each case. 

TABLE XXVIIL 

RADIATION : EXPERIMENT NO. 1. 



RADIOMETER NO. 



Water heated, lbs. 
Mean t, initial 

Mean t, final 

Mean increase, deg 



8.797 
78.16° 
95.40° 
17.24° 



8:45 

9 

9:15 

9:30 

9:45 



TEMPERATURE OF WATER. 



Initial. 
Degrees F. 



76. 8 C 

77. 4 C 
78. C 
78. T 
79. 9 C 



Mean 

B. t. u 

B. t. u., increase . 
B. t. u., total, 1 hr 



78.16° 
78.1923 



Final. 
Degrees F. 



98.8° 
92.3° 
97.9° 
93.0° 
95.0° 



95.4° 

95.4642 

17.2719 

151.9409 



RADIOMETER NO. 2. 



Water heated, lbs. 
Mean t, initial 

Mean t, final 

Mean increase, deg 



15.563 

77.32° 
93.10° 
15.78° 



8:45 

9 

9:15 

9:30 

9:45 



Mean .... 
B. t. u . . . 

B. t. u., increase . 
B. t. u., total, 1 hr 



TEMPERATURE OF AVATER. 



Initial. 
Decrees F. 



76.5° 
76.3° 
76.9° 

77.0° 
79.9° 



77.32° 
77.3506 



Final. 
Degrees F. 



91.0° 
93.8° 
93.0° 
92.0° 

95.7° 



93.10° 

93.1612 

15.8106 

246.0604 



138 



TBIALS OF A WARM-BLAST APPABATUS. 







TABLE 


XXIX. 








RADIATION : EXPERIMENT NO. 2. 




RADIOMETER NO. 


1. 


RADIOMETER NO. 2. 


Water heated 


, lbs 


13.105 


Water heated, lbs 


23.699 


Mean t, initial 


1 


85.37° 

109.47° 

24.10° 


Mean t, initi 
Mean t, final 
Mean incrca 


al 


79.91° 


Mean t, final. 






109.93° 


Mean increase 


S deg 


se, deg 


30.01° 




TEMPERATUR 


E OF WATER. 


TIME. 


TEMPERATURE OF WATER. 


TIME. 


Initial. 


Final. 


Initial. 


Final. 




Degrees F. 


Degrees F. 




Degrees F. 


Degrees F. 


10 


87.8° 


105.2° 


10 


79.0° 


100.0° 


10:15 


75.2° 


105.3° 


10:15 


78.0° 


105.0° 


10:30 


78.7° 


101.8° 


10:30 


78.5° 


108.5° 


10:45 


79.6° 


103.0° 


10:45 


79.0° 


111.6° 


11 


79.5° 


104.0° 


11 


79.0° 


114.5° 


11.15 


80.3° 


105.0° 


11:15 


79.5° 


117.0° 


11:30 


80.7° 


105.5° 


11:30 


77.0° 


109.0° 


11:45 


81.7° 


106.0° 


11:45 


79.5° 


109 0° 


12 


87.8° 


109.0° 


12 


88.3° 


112. 3 


12:15 


90.5° 


111.2° 


12:15 


89.1° 


112.5° 


12 30 


93.1° 


114.3° 


12:30 


77.5° 


112.2° 


12:45 


94.7° 


120.2° 


12:45 


79.0° 


107.0° 


1 


96.0° 


119.5° 


1 


78.2° 


108.4° 


1:15 


96.6° 


121.0° 


1:15 


78.0° 


110.2° 


1:30 


78.4° 


111.0° 


1:30 
Mean 


79.0° 


113.0° 


Mean 


85.37° 


109.47° 


79.91° 


110.00° 


B. t. Ll 


85.4157 


109.5784 


B. t. u 


79.9458 


110.1100 


B t. u incr 


-ase 


24.1627 
316.6522 


B. t. u., incr ase 

B, t. u., total, 3.5 his... 


30.1642 


B. t. II., total 


, 3.5hrs.... 


714.8614 


B. t. u., per 1 
B. t. u., Mea 


lour 


90.4721 


B. t. u., per hour 


204.2461 


i, 4.5 lirs 


104.1318 


B. t. u., mean, 4.5 hrs. . . 


203.4015 



The tables present some striking anomalies, but some coincidences 
no less striking. 

The result obtained from radiometer No. 1, is very much less than 
that obtained from No. 2 — only 62 per cent, as much in the first hour, 
experiment No. 1; only 44 per cent, in the following 3.5 hours, ex- 
periment No. 2 ; and for 4.5 hours, taking both experiments together, 
51 per cent. 

There was certainly no corresponding difference in the radiation 
from the two parts of the smoke-box cover, which were only a few 
inches apart, and almost certainly of equal temperature. The dif- 
ference here noted in the apparent radiation is at once too large 
and too uniformly persistent to be explained by any errors of ob- 



RADIATION FROM BRICK- WORK. 139 

servation. Two explanations suggest themselves, which, singly or 
in conjunction, may account for it. 

First, radiometer No. 1 may not have been so adjusted to the 
brick-work as entirely to cut of! circulation of air, and consequent 
loss of heat by convection ; and second, radiometer No. 2 may have 
been, to some extent, in contact with the smoke-box cover, so as to 
receive some heat by conduction. The object of these prelimin- 
ary experiments was to test the accuracy of the radiometers, and 
the intention was to divide the area of the brick-work into por- 
tions of about one square yard, and to apply the radiometers in turn 
to each and all of these partial areas. The first results were not 
satisfactory, and circumstances did not permit the prosecution of 
this inquiry. The date of these experiments, August 10, 1881, 
falls in the week ending August 13, week E. The coal burned 
that week was 14,670, pounds of evaporative power equal to the 
evaporation of 13.61 pounds of water from and at 212° F., and 
therefore capable of producing: 

14670 x 13.64 x 965.7 = 193235411 B. t. u. 

Loss from imperfect combustion was 1.81 per cent. The loss by 
radiation from brick- work, for week E., appears to be 1.39 per cent.; 
but this is a residuum, and is affected by many small errors. It is 
therefore proper to take the mean for the six weeks, July 16 to 
August 20, which was 2.81 per cent. 

Now, 1.81 per cent, of 193235411 = 3497561, and 
subtracting 3497561 



we have 189737850 as the number of British ther- 

mal units actually produced in week E. Taking 2.81 per cent, of the 
heat produced — 5331634 British thermal units, going on day and 

(rooi C{QA_ 

night, say 132 hours per week, we have — —^ — = 40391 B. t. u. per 

hour. The total radiating surface of the Pacific boiler setting was 

about 1000 square feet, and dividing by this number the quantity 

40391 
of heat radiated per hour, we have, ^ = 40.39 B. t. u. per 

square foot per hour. If this be the mean radiation from the whole 
outside surface of the brick-work, the rate must be much greater 
directly opposite the fire. If 2.5 times as much, it would be 40.39 
x 2.5 — say, 101, about equal to the quantity shown by radiometer 
No. 1, and about half as much as appears by No. 2. But these ex- 
periments were upon the iron cover of the smoke-box, where the 



140 



TRIALS OF A WARM-BLAST APPARATUS. 



radiation was probably considerably more rapid than from the brick- 
work, although the internal temperature was low. Inconclusive 
as were these experiments, the apparatus appears to have elements 
of usefulness, and may, with patience and care, yield valuable in- 
formation. 

Transmission of heat theough brick- work. — All the heat ra- 
diated from the surface of the brick-work must of course reach the 
surface from within by conduction. 

For studying the conduction the following provision was made, 
Round wooden rods, about 1.5 inches in diameter, a little tapering, 
were laid, horizontally and transversely, in the side wall of warm- 
blast boiler No. 2, in two rows, respectively 4' 5" and 5' 0" above the 
floor, 14 inches apart in each row, those in the upper row being placed 
centrally over the spaces between those in the lower row. There 
were 7 in each row, penetrating respectively 4, 8, 12, 16, 20, 24, 
and 28 inches ; the latter, therefore, having only the width of one 
fire-brick (4.5") between its extremity and the combustion cham- 
ber, about midway between the bridge wall and the pier. On the 
withdrawal of the rods, holes were left for the insertion of ther- 
mometers to the several depths above mentioned. 

The position of the deep and shallow holes was reversed in the 
two rows, so that the 4" holes in each row were near the 28" holes 
in the other. This arrangement will be clearly seen in Fig. 181. 




12' 5" 



JjD* 



CA B 

Fig. 22. 
horizontal section of brick-work of warm-blast boiler ; showing the loca- 
tion of holes for taking temperatures. 

Three sets of observations were taken in these holes; the first, 
during all the working hours of one week, quarter-hourly — Monday 
morning, September 19, to Saturday noon, September 24, 1881, in 
the 28-inch hole, A, Fig. 181, in the lower row, located 12' 5" from 
the front end, and 8" above the level of the lower side of boiler. 
The observed temperatures are all given in Table XXX., and repre- 



CONDUCTION THROUGH BEICK-WOEK. 



141 



TABLE XXX. 

TEMPERATURES OF BRICK-WORK, WARM-BLAST BOILER NO. 1, 12' 5" FROM 
FRONT END, — 2' 5" ABOVE GRATES, — 28" FROM OUTSIDE, 4.5" FliOM INSIDE 
OF SIDE WALL,— MONDAY, SEPT. 19, 7 h. 30 m. A.M., TO SATURDAY, SEPT. 24, 

12 h. 15 m. p.m., 1881. by mercukial thermometer: quarter-hourly 

READINGS. SEE PROFILE, FIG. 183. 





Monday. 


Tuesday. 


Wednesday. 


Thursday. 


Friday. 


Saturday. 


TIME. 


19 


20 


21 


22 


23 


24 


H. M. 


Degree? F. 


Degrees F. 


Degrees F. 


Degrees F. 


Degrees F. 


Degrees F. 


7 A.M. 




354 


344 






390 


15 




358 


344 


330 


360 


392 


30 


244 


360 


344 


323 


360 


384 


45 


240 


356 


341 


323 


356 


383 


8 


239 


355 


340 


320 


360 


385 


15 


240 


358 


340 


325 


360 


385 


30 


240 


357 


341 


327 


363 


384 


45 


242 


360 


341 


329 


363 


386 


9 


242 


362 


346 


349 


363 


383 


15 


246 


362 


350 


350 


370 


382 


30 


248 


354 


344 


334 


372 


383 


45 


254 


358 


344 


340 


374 


384 


10 


256 


364 


346 


340 


374 


388 


15 


260 


368 


346 


332 


378 


384 


30 


264 


368 


348 


348 


382 


384 


45 


268 


370 


348 


350 


384 


384 


11 


272 


372 


348 


352 


386 


386 


15 


278 


372 


348 


350 


386 


386 


30 


270 


374 


346 


354 


394 


386 


45 


280 


374 


348 


3o8 


397 


386 


12 M. 


294 


376 


350 


362 


399 


386 


1 5 p;m. 


300 


378 


352 


364 


401 


386 


30 


302 


378 


354 


366 


. 403 




45 


308 


380 


354 


366 


404 




1 


312 


380 


354 


366 


414 




15 


316 


382 


354 


366 


415 




30 


320 


383 


357 


372 


416 




45 


323 


384 


358 


373 


420 




o 


337 


386 


358 


373 


421 




15 


342 


386 


358 


374 


428 




30 


347 


388 


359 


375 


430 




45 


350 


390 


362 


374 


434 




3 


350 


390 


362 


376 


438 




15 


358 


392 


362 


374 


435 




30 


358 


394 


356 


378 


436 




45 


370 


398 


354 


374 


444 




4 


372 


394 


364 


374 


444 




15 


378 


398 


364 


376 


450 




30 


384 


398 


364 


376 


450 




45 


384 


392 


366 


376 


450 




5 


392 


394 


362 


384 


452 




15 


392 


394 


364 


386 


454 




30 


394 


394 


364 


388 


452 




45 


400 


394 


362 


392 


452 




6 




394 


364 




452 





142 



TRIALS OF A WARM-BLAST APPARATUS. 



Fig. 23. GRAPHICAL REPRESENTATION OF 
TABLE XXX. SCALES, 4 HOURS=><2'.'80=^^ 
400 ° IX O 1H2 t 

SUJj'j JXIL ^Saturday^pppTjt Frida y 



j Thursday 



sented graphically in Fig. 23 and Fig. 24. In Fig. 23, the sev- 
eral daily profiles would, if all drawn from the same base-line, con- 
fuse each other. The 400° line is therefore raised for each succeed- 
ing profile, enough to permit all to be clearly seen. The waving 
lines connect the points observed, of which there were on Monday, 
42, on Tuesday and Wednesday, 45 each, on Thursday 43, on Fri- 
day 44, and on Saturday 22, making 241 in all. 

These waving lines repre- 
sent, for the most part, if not 
always, real fluctuations of tem- 
perature. Every opening of a 
fire-door sent a pulse of low 
temperature through the brick- 
work, and this was sharply felt 
so near as 4.5 inches to the 
source of heat. The smooth 
curves are intended to represent 
approximate mean ranges of 
temperature. On Monday the 
temperature remained station- 
ary, indeed fell 4° or 5° while 
the banked fire was opened, and 
fresh coal put on, but from 8:30 
rose sharpty, although not quite 
uniformly, to the close, and 
reached 400°, a point not again 
attained until noon of Friday. 
The effect of light firing and 
early banking is distinctly seen on Tuesday and Wednesday. On 
Friday, the fire was driven hard at midda} 7 . This was the day on 
which an experiment was made to ascertain the power consumed in 
driving the blower, when the speed of the engine was 191 revolu- 
tions per minute, and that of the blower, 232, resulting in a rate of 
combustion equal to 16.63 pounds of coal per square foot of grate 
per hour. Fig. 24 shows the same mean curves on the same verti- 
cal scale, combined with a horizontal scale one-sixth as large, and 
the intervening nights, in which the temperature is represented by 
dotted lines, connecting the last observation of each day with the 
first of the day following. From Saturday noon, when the fire 
was drawn, the dotted line is seen sloping away to reach some low 
point on the following Monday morning; but the form of this 







CONDUCTION THROUGH BRICK-WORE. 



143 



Fig. 24. 


GRAPHICAL REPRESENTATION OF TABLE. XXX. VERTICAL SCALE AS IN FIG. 182, 80°ToJj- 


HORIZONTAL SCALE, 24 HOURS TO^'lNCH. IN BRICK-WORK l2'll"FROM FRONT END, 2VABOVE 


GRATES; 4. 5*FROM INSIDE. 




400° r 


/ 










X ] 


f 


\ 


l/ 


iV 


N 


1 




K L 

\ 


S00° | 1/ 


12 ! 


M. 


12 I 


M". 


12 I 


ivi. 


12 1 


M. 


12 i 




N 


[ 


<yDay. 


Night.! 


Day. 


J | 

I 
Night.; 


Day. 


Night. | 


Day. 


Night.j 


Day. 


Night.j 


Da 




Monday 


Tuesday 


Wednesday 


Thursday 


Friday 


Satur'y 


2M° J 


19 


20 


21 


22 


23 


21 





curve and of the night curves, is conjectural, no night observations 
having been taken. 

Table XXXI. presents a record of 24 observations at each of 3 
holes, severally 8", 16 ', and 24" in depth, and therefore 20.5", 
16.5", and 8.5" from the lire, taken on Monday, February 13, 1882. 
In Fig. 25, these observations are arranged in the form of three 
profiles upon the interval of time, 5 h. 45 m. as a base. The assumed 
means, represented by the full, smooth curves, are here a little 
more arbitrary ; but this is, as will be seen, of no importance. 



Fig. 25. 

GRAPHICAL REPRESENTATION OF TABLE XXXI 

FEBRUARY 13. 1882 

TEMPERATURES IN BRICK-WORK. 




Fig. 26. 

QUARTER-HOURLY MEAN TRANSVERSE TEMPER 
ATURES IN BRICK-WORK: FROM TABLE XXXI. 

FEB.I3.I882. |4 15 

500 F 




144 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE XXXI. 

TEMPERATURE OF BRICK- WORK OF WARM-BLAST BOILER SETTING NO. 1, AT 
VARIOUS DEPTHS, NAMELY, 8 INCHES, 16 INCHES AND 24 INCHES FROM THE 
OUTER SURFACE: 10 h. 30 m. A.M. TO 4 b. 15 m. P.M., MONDAY, FEBRUARY 

13, 1882. see fig. 184. 5 feet above floor. 



TIME. 


8 

inches 

from 

outside. 


16 

inches 

from 

outside. 


24 

inches 

from 

outside. 


TIME. 


8 

inches 

from 

outside. 


16 

inches 

from 

outside. 


24 

inches 

from 

outside. 


H. M. 


Deg. F. 


Deg. F. 


Deg. F. 


H. M. 


Deg. F. 


Deg. F. 


Deg. F. 


10 30 A.M. 


180 


230 


294 


1 30 P.M. 


220 


352 


392 


45 


182 


232 


316 


45 


220 


348 


4L5 


11 


184 


242 


332 


2 


224 


368 


397 


15 


186 


246 


334 


15 


222 


385 


425 


30 


186 


272 


344 


30 


252 


384 


446 


45 


186 


272 


361 


45 


252 


374 


459 


12 M. 


190 


274 


361 


3 


252 


376 


453 


15 P.M. 


203 


276 


360 


15 


274 


431 


490 


30 


215 


279 


359 


30 


244 


480 


513 


45 


215 


282 


357 


45 


248 


487 


519 


1 


217 


286 


C56 


4 


290 


468 


513 


15 


220 


311 


C81 


15 


293 


469 


515 



Fig. 26 represents these assumed mean temperatures as a suc- 
cession of profiles upon the thickness of brick-work they embrace 
(16 inches), as a base, by full lines at the hours, and dotted lines at 
the quarters of an hour. 

Fig. 27 represents in the same manner as the preceding figure, 
the hourly profiles, by the temperatures actually observed ; agree- 
ing in general configuration with the last figure, but differing in 
detail, and presenting a little less range in consequence of the 
omission of two lines before 11, and one line after 4 o'clock. 

Fig. 28 is similar to the two preceding, except that here all the 
quarter-hourly lines are drawn from the actual observations, and 
embody all the irregularities of the waving lines of Fig. 25. 

This table is noticeable for the high temperature found, especially 



CONDUCTION THROUGH BRICK- WORK. 



145 



Fig. 27. 




ACTUAL HOURLY TEMPERATURES IN BRICK- 


WORK: FROM TABLE XXXI. 




MONDAY, FEBRUARY 13. 1882. 


500 F. 







4 P.M. 
3 P.M. 






4 


6 


/^ o 








400°F5 ; 
£ 

o 




.__„^__ 





2 P.M. 










<H 


/ > 


Is 




12 M. 


a 








1P.M. 


lO 








11A.M. 


300° « 
4 


/ ss ^ 








// i" 


















/ / ^s^s^ 


/^ 






3 


/ ^^S^ 




^ 




2 




11 


s 




200° * 


^s^\^^ • 








12 






.... . ..p 




11 












"O 




T3 




•o 




















100 * 


§ 




p 














o 


£ 




£ 






o 








o 


«w 




«H 




C 


.£ 




c 




F.<» 


«> 




-* 







Fig. 28. 




QUARTER-HOURLY ACTUALTEMPERATURES IN 
BRICK-WORK: FROM TABLE XXXI. 




FEB. 13. 1882. 




500 F. 






4 P.M. 










3 P.M. 


400° 


/yy/ s^ ® 


——^^ri---. 


g^= 


2 P.M. 

12 M. 
1 P.M. 

11A.M. 


300° 

I 
g 
o 

200° ri 






£ 


10.30 


-"^^ \a 




c 

00 


100° 1 


0) 

■1 




"2 

3 




£ 
o 


1 
* 




£ 




.£ 


.£ 




.3 




0F.=o 


5© 




aK 





in the 16-inch hole, and notably in the last five observations — 431 
to 487 degrees. 

Table XXXII. embraces 34 sets of observations in 3 holes sever- 
ally, 4", 16", and 28" deep. The 16" hole is not identical with the 
16" hole of Table XXXI., but is only 7" from it horizontally, and 



Fig. 29. 

GRAPHICAL REPRESENTATION OF TABLE XXXII, 

FEBRUARY 14. 1882. 

TEMPERATURES IN BRICK-WORK: 

28 in. 



500 F. 




Fig. 30. 



HOURLY MEAN TRANSVERSE TEMPERATURES 
IN BRiCK-WORK: FROM TABLE XXXII. 

TUESDAY. FEBRUARY 14. 1882. 




146 



TRIALS OF A WARM-BLAST APPARATUS. 



TABLE XXXII. 

TEMPERATURE OP BRICK- WORK OP WARM-BLAST BOILER SETTING NO. 1, AT 
VARIOUS DEPTHS, NAMELY, 4 INCHES, 16 INCHES, AND 28 INCHES FROM THE 

outer surface: 8 h. 15 m. a.m. to 4 li. 30 m. p.m., Tuesday, February 

14, 1882. 5 FEET ABOVE FLOOR. 



TIME. 


4 

inches 

from 

outside. 


16 

inches 

from 

outside. 


28 

inches 

from 

outside. 


TIME. 


4 

inches 

from 

outside. 


16 

inches 

from 

outside. 


28 

inches 

from 

outside. 


H. M. 


Deg. F. 


Deg. F. 


Deg. F. 


H. M. 


Deg F. 


Deg. F. 


Deg. P. 


8 15 a.m. 


118 


267 


283 


12 30 p.m. 


150 


319 


355 


30 


140 


285 


297 


45 


150 


319 


382 


45 


140 


292 


316 


1 


150 


317 


389 


9 


141 


290 


321 


15 


150 


350 


418 


15 


142 


294 


323 


30 


164 


353 


460 


30 


141 


299 


341 


45 


166 


349 


466 


45 


141 


296 


352 


2 


175 


319 


466 


10 


141 


296 


352 


15 


182 


330 


471 


15 


142 


320 


348 


30 


182 


274 


476 


30 


142 


308 


362 


45 


180 


308 


479 


45 


142 


306 


359 


3 


180 


300 


481 


11 


142 


302 


365 


15 


181 


300 


488 


15 


J 42 


298 


370 


30 


180 


302 


495 


30 


142 


292 


376 


45 


180 


310 


498 


45 


142 


296 


382 


4 


180 


306 


503 


12 M. 


149 


318 


354 


15 


180 


304 


506 


15 P.M. 


150 


313 


369 


30 


180 


298 


509 



the same distance vertically, and therefore only 10" from it in a 
direct line. 

The three profiles, Fig. 29, are separated by 12 inches of brick- 
work. They are noticeable for the sudden rise in the first 15 minutes, 
at 4", and in the first 30 minutes, at 16" and 28" ; for the great de- 
pression, 12 m. to 1 p.m., at 28", the still greater depression, 2:30 
to 4:30, at 16", caused by keeping fire-doors open to prevent blow- 



CONDUCTION THROUGH BRICK-WORK. 



147 



ing off steam at the safety-valve ; and in the 4" hole by the two 
well marked level lines— 8:30 to 11:45, and 2:15 to 4:30, with the 
intermediate steps. The dotted curves which indicate assumed 
means in this figure are rather violent assumptions, especially at 
16" ; but this, again, will be seen to be of no importance. 

Fig. 30, showing hourly mean transverse temperatures, Fig. 31, 
showing hourly actual transverse temperatures, and Fig. 33, show- 
ing quarter-hourly actual transverse temperatures, being similar in 
construction to figures already described in connection with Table 
XXIX., require no comment. 



Fig. 31. 

HOURLY ACTUAL TEMPERATURES IN BRICK- 
WORK: FROM TABLE XXXII. 

TUESDAY. FEBRUARY 14. 1882 




Fig. 32 GRAPHICAL REPRESENTATION OF EX- 
TREME TEMPERATURES IN BRICK WORK: FROM 
TABLES XXX, XXXI, AND XXXII, 




In Fig. 32, the extreme temperatures — highest and lowest — of 
all three tables, XXVIII., XXIX., and XXX., are grouped together 
in their appropriate positions in the brick-work. The full vertical 
line M N represents the entire range of the 241 quarter-hourly ob- 
servations in the 28-inch hole, during the week Sept. 19-24, 1881. 

The curved line ABC represents the upper, and the line DEF 
the lower temperatures, observed on Monday, February 13, 1882; 
and the shaded space between these lines and the vertical dotted 
lines at 8" and 24" from the outside, represents the whole range of 
the 72 temperatures observed on that day. 



148 



TRIALS OF A V/ARM-BLAST APPARATUS. 



The oblique, nearly straight line, G H I, represents the upper, and 
the sharply bent line J K L, the lower temperatures observed on 



Fig. 33. 

ACTUAL QUATER-HOURLY TEMPERATURE IN BRICK-WORK: 
FROM TABLE XXXII TUESDAY, FEBRUARY 14. 1882. 



500°F. 




Tuesday, February 14, 1882 ; and the shaded space bounded by 
these two lines and by the 4-inch and 28-inch verticals, represents 
the entire range of the 102 observed temperatures on that day. 



BEICK-WOEK A HEAT-RESERVOIR. 149 

Tlie form of the curves of transmission, whether convex or con- 
cave upward, or straight, depends on the relation of the increment 
of heat at the inner surface, to the conductivity of the brick- work. 

In Fig. 31, the hourly lines at 3 and 4 p.m., and Fig. 33, all 
the lines from 2 to 4:30, are concave upward, showing that heat 
was received at the inner face of the wall faster than it was con- 
ducted away. In Fig. 28, the 12 m. line is almost exactly straight, 
showing a balance of heat received and conducted ; the lines below, 
especially those at 10 to 11:15, are concave upward, showing that 
heat is received at the inner face faster than it is conducted out- 
ward ; and the upper lines, 2 to 4:15, are convex upward, showing 
that heat is conducted outward faster than it is received at the in- 
ner face. 

Careful study of these diagrams will clearly teach the importance 
of thick walls around boiler furnaces. If the wall shown in section 
in Fig. 32 were, as is too commonly the case, only 16 or 16.5 
inches in thickness, the temperature of the outer surface would 
never rise to 400° or 500° F., because the more active radiation 
would disperse the heat more rapidly; but this more active radia- 
tion would imply a higher temperature than here prevails at the 
outer surface, perhaps as high as is here found at a depth of 4 to 
6 inches, say 120° to 200° F. The mass of brick masonry consti- 
tuting the inner foot in thickness of a wall two feet or more in 
thickness, is no mean equalizer of temperatures in the furnace and 
combustion-chamber of an externally fired boiler. Taking into 
consideration only five feet in height and one foot in thickness on 
each side of the- furnace, and 26 feet in length (including the cross- 
wall in rear), we have 2 x 5 x 26 = 260 cubic feet, weighing 100 
lbs. per cubic foot, of one-fifth the specific heat of water, equal 
therefore to 20 lbs. of water per cubic foot ; and 260 x 20 = 5200. 
A range of temperature of 200°, from 250° to 450° F., will there- 
fore imply an increase or diminution in the quantity of heat of say 
1 000,000 British thermal units, equal to the evaporation from and 
at 2 12° F. of more than 1,000 pounds of water. Eadiation from 
brick-work to boiler is rapid and constant, and tends sensibly to 
maintain uniformity in the transmission of heat to the boiler and 
its contained water, when the fire-doors are opened for firing, or 
for cleaning the grates, and when the grates are covered with 
freshly fired coal not yet fully ignited. The ideal boiler setting 
will contain, among other things, a series of three-eighths inch iron 
pipes, welded up at the lower end, inserted vertically, at various 



150 



TEIALS OF A WAEM-BLAST APPAEATUS. 



distances from the outer surface of the walls, and to various depths, 
to contain mercury, for the more complete study of the subject 
under consideration by the patient and long continued use of the 
thermometer. 

Power consumed in driving blowee. — The Root blower was 
driven by a Hoadley portable steam engine detached from its 
boiler, made by Geo* T. McLautblin & Co., Boston, 5.5 inches diam- 



57.7t 1- -^-sc—A; 




Atm. 



Vac.. 



Fm. 34. 




eter of cylinder, and 8 inches stroke, easily capable of producing 
9 horse-power, indicated. Its automatic cut-off was adjustable be- 
tween the limits of 125 and 325 revolutions per minute, by means 
of a change of links confining the ends of the governor springs. 

Steam pressure varied rapidly and widely on account of the vari- 
able requirements of the chemical works for steam, so that without 
automatic cut-off no tolerable regularity of speed could have been 
maintained. 



POWEE USED IN DRIVING BLOWER. 



151 



Indicator diagrams were taken from both ends of the cylinder 
under various conditions. Two pair of these are given exactly as 
they were taken, save that they are here reduced to half their 
original length, the scale of pressures unaltered. In both cases 
the speed was 200 revolutions per minute. In Fig. 34 the engine 
was exhausting into the air, and the back pressure was only about 
15 pounds absolute. In Fig. 35 the engine was exhausting into 
an extemporized surface condenser with about 3.8 pounds per 
square inch back pressure, above the atmosphere, equal to 18.5 
pounds absolute. Clearance, ascertained by filling the space with 
water, was equal to 15 per cent, of the volume swept through by 
the piston, allowance being made for the volume of the piston-rod 
at the end nearest to the crank. 

There is evidence of leakage in the compression lines. The 
power shown- in Fig. 31 is 2.96 horse-power indicated. The 
quantity of visible steam exhausted is equal to 40.86 pounds per 
horse-power per hour. 

In Fig. 35 the power is 2.77 horse-power indicated, and the 
quantity of visible steam is 43.1 pounds per horse-power per 
hour. On the 23d day 
of September, 1881, a 
very careful experiment 
was made to ascertain 
the quantity of heat re- 
jected by the engine while 
driving the blower, by 
condensing all the steam 
from the exhaust pipe, 
and noting the quantity 
of water used for condens- 
ing and its initial and 
final temperature. For 
this purpose the steam 
calorimeter previously 
described was used. 

Water from a cask 
placed on a roof, main- 
tained at a constant level 
by a "ball and cock," 
was led by pipes to the interior of the calorimeter and distributed 
by seven pipes of three-quarter inch gas pipe, one passing down 



POUNDS TO 1 INCH. 
Piston, 5.5 in. 

iston, 23.158 Sq. in. 
: Stroke. 8 in. 
>. perm. 190.945 




Mean of diagrams taken while condensing tie ex. Steam. 

Fig. 36. 



152 TEIALS OF A WAKM-BLAST APPARATUS. 

the center in the space usually occupied by the shaft of the agita- 
tor, and the other six spaced equally around the sides between the 
calorimeter lining and the steam drum. Water was supplied to 
these pipes equally by branches from a vertical, centrally located 
two-inch pipe extending from the cask. 

The water so supplied proved to be adequate to condense the 
steam at only three to four pounds pressure above the atmosphere 
(Fig. 36). A weir was litted to the top of the calorimeter to dis- 
charge this water through a spout into a cask placed conveniently 
near on scales. Delicate and accurate thermometers having their 
bulbs immersed in small vials filled with oil were placed in the in- 
flowing and outflowing streams, and the temperature they indi- 
cated was noted once a minute. The oil in which the bulbs were 
immersed served to integrate the momentary variations of ten> 
perature due to imperfect mixing, so that the changes were moder- 
ate both in rapidity and extent. 

Time of beginning the experiment, p. m 4 h. 13 ra. 58.5 s. 

Time of ending the experiment, P. M 5 h. 35 m. 9.0 s. 

Duration of experiment 1 h. 21 m. 10.5 s. 

rr 1 3.-529166 h. = 81.175 m. = 4870.5 seconds. 

Reading of counter on engine, final 3122000 

Reading of counter on engine, initial 3106500 

Number of revolutions of engine in 81.175 minutes. . . . 15500 

Mean number of revolutions of engine per minute 190.9455 

Mean velocity of piston in feet per minute 254.59 

Flow of water over weir, 413 lbs. in 5 m. 56.00 s. 

Again, 413 lbs. in 5 m. 55.50 s. 

Again, 413 lbs. in 5 m. 55.25 s. 

Mean flow of water over weir, 413 lbs. in 5 m. 55.58 s. 

Total quantity of water in 81.175 minutes, lbs 5657. 

Quantity of water per minute, lbs 69.689 

Quantity of water per hour, lbs 4181.34 

Quantity of water per horse-power per hour, 2.08 

indicated horse-power, lbs 2010.26 

Total quantity of exhaust steam and entrained and 

condensed water, lbs 237. 

Steam and entrained and condensed water per hour, 

during 1.3529 hours, lbs 175.18 

Steam and entrained and condensed water per horse- 
power per hour ; 2.08 indicated horse-power, lbs 84.22 

Ratio of condensing water to steam 23.87 

Mean final temperature of condensing water 109.9° F. 

Mean initial temperature of condensing water 68.2° F. 

Mean rise of temperature 41.7° F. 

Number of B. t. u. added to each one pound of water = 
110.0047- 68.2683, B. t. u 41.7364 






POWEE USED IN DRIVING BLOWER. 153 

Total number of B. t. u. added to 5657 lbs. of water in 
81.175 m 236102.8 

Mean temperature of condensed steam 94.9° F. 

Difference in quantity of lie it between water at 94.9° F. 
and at 68. 2 ° F. = 94.98 18 - 63.2333 = B. t. u. . , 26.6965 

Quantity of heat carried off by water condensed from 
steam (237 lbs.) above initial temperature of condens- 
ing water = (94.9648 - 68.2683) x 237 = B. t. u . . 6327.1 

Total quantity of heat rejected by the engine and 

found in the condenser, 236102.8 + 6327.1 = B. t.u 242429.9 

Power represented by the mean indicator, diagram, Fig. 
195; mean of five diagrams taken from the end of the 
cylinder farthest from the crank; three others, sub- 
stantially like these, being slightly imperfect, are re- 
jected. I. h. p 2.263 

Ratio of the mean power at the two ends of the cylinder 
to the power developed at the end farthest from crank, 
per cent 91.78 

Power developed at both ends of the cyl., 2.636 x .9178 

= i. h. p 2.08 

British thermal units equal to 2.08 indicated h. p. during 
81.175 minutes, 

2.08 x 33000 x 81.175 _ + 
= =g = B. t. u, 7217.42 

Steam pressure, absolute, in condenser, lbs. per sq. in. . . 18 

Heat, above 0° F. contained in one pound of steam of 18 
lbs. pressure per sq. in absolute, B. t. u 1181.7640 

Heat above 0° F. contained in one pound of water of tem- 
perature of condensed steam, 94.9° F., B. t. u 94.9648 

Quantity of heat to be subtracted from one pound steam 
of 18 lbs. per sq. in. pressure absolute, to condense it 
to water of 94.9° temperature, B. t. u 1086.7992 

Number of pounds of steam of 18 lbs. per sq. in. p. 
abs. condensed by convertion of heat into work in 
the engine, 2.08 i. h. p. during 81.175 minutes, 

7217.42 IT, 
= 108O992 = lbS 6M1 

Per horse-power per hour, 
6.64 x 60 
2.08 x 81.175" JbS 2 ' S{} 

Number of pounds of visible steam, according to indica- 
tor cards, per horse-power per hour, lbs 41.77 

Quantity of steam, visible, and condensed in doing work, 
per h. p. per hour, 2.36 x 41.77 = lbs 44.13 

Quantity of entrained water, condensation in pipes and 
cylinder (not in doing work), and leakage ; being the ex- 
cess of total steam and water admitted to steam drum 
(237), over visible steam and steam condensed in doing 
work (124 lbs.), per i. h. p. per hour, 



154 TEIALS OF A WAKM-BLAST APPARATUS. 

237 x 60 AlHa 

"81.175 x *T08 ~ 44 13 ' = lbs 40-09 

Ratio of excess to steam visible : 

40.09 

44^13 " - 9084 > = P^ cent 90.84 

Ratio of excess to total : 

40.09 

8422 = 6 ' = per cent 47.6 

Ratio of visible steam, etc., to total : 

44.13 

8422 = ' 524 ' = pei * cent 52.4 

Speed of blower corresponding to 191 rev. of engine per 

minute ; m 2.32 

Rate of combustion of anthracite corresponding to 232 
rev. of blower per m. (232 x .07169), in pounds of coal 
per sq. ft. of grate area per hour (by experiment) 16.63 

Pounds of coal burned per hour on lire-grate, 
16.63 x 25.83 = lbs 430 

Pounds of water evaporated from and at 212° F. per hour, 
430 x 11.71 lbs- 5035. 

Ratio of all water passing through the engine to water 
evaporated, 

-5035- = - 03 5 = per cent 3.5 



This engine, then, was using 3.5 per cent, of all the water evap- 
orated ; but at the rate of 84.22 pounds of water per horse-power 
per hour. If power were supplied from a large engine, of good 
construction, 24 pounds of water per horse-power per hour would 

24 

be sufficient ; and = .287, and .287 x 3.5 = 1. 

Therefore, the steam required to drive the blower, with a reason- 
ably good engine, running with 24 pounds of water per indicated 
horse-power per hour, is 1 per cent, of the steam generated by its 
use. 

It may be worth noting that the circumference of the engine- 
pulley was 113.30 inches, and that of the blower pulley, 92.87 
inches. The number of revolutions made by the engine and 
blower respectively, during weeks G, ending February 4, and H, 
ending February 11, 1882, and the running time each week, were : 

Eunning Whole number of revolutions 

time. of of 

Minutes. Engine. Blower. 

Week G 3272 542624 659808 

Week H 3156 508 176 616088 

Total, 107 h. 8 m. = 6 428 1 050 800 t 275 896 






SOLID CAKBON IN FLUE GASES. 155 



The ratio of these numbers is : 

1275896 
LU50800 



= 1.2142 



liq o 

and g| ? = 1.2200 

Difference = " slip " = .0058 — say about 0.6 per cent. 

Solid carbon and ash in flue gases. — During the week ending 
August 20, 1881 (week F), the fuel being bituminous coal, an ex- 
periment was made by Mr. Prentiss to determine the quantity of 
solid matter — finely comminuted carbon and ash — borne off in the 
cloud of black smoke which to vulgar apprehension appears to pre- 
sent a formidable loss of combustible material, and is in fact a pal- 
pable and serious nuisance. 

A stream of gas directly from the flue was drawn by an aspira- 
tor through a gas meter, to measure its volume ; and as its pressure 
and temperature were observed, and as the error of the gas meter 
was ascertained, the weight of the gases became known. The 
stream of gas — smoke — was made to pass through a strainer of 
muslin, in the form of a bag, secured at the bottom of a vessel of 
water, which retained, mechanically, some of the soot, and caused 
the rest to be diffused and retained in the water, while the gas bub- 
bled up and escaped from the water perfectly clear. When a suf- 
ficient and known quantity of the gases had been so passed, the 
water was evaporated, and the residuum was dried and weighed. 

One hundred cubic feet by the meter, equal to 108.53 cubic feet 
corrected, at 72° F., weighing 534 grains = 0.0762857 lb. per 
cubic foot, yielded 0.49 gramme = 7.57 grains = 0.001081 lb. of 
solid matter; and 1 cubic foot, therefore, yielded 0.00001 lb. 

The quantity of coal burned during the week, was 12890 lbs. ; 
the mean quantity of flue gas per lb. of coal was 25.23 lbs. ; and the 
total quantity of flue gas was 25.23 X 12890 = 325215 lbs. 

The volume of this gas, at 72° F., was 

325215 -T- 0.0762857 = 4263119 cubic feet, 

yielding 4263119 x .00001 = 42.63 lbs. of solid matter— soot. The 
ratio of this soot to the total quantity of coal burned is, 

^J? = .0033 = 0.33 per cent. 

No analysis was made of this solid matter, as there seemed to be 



156 TRIALS OF A WAKM-BLAST APPARATUS. 

no way of completely separating it from the muslin bag, and the 
quantity was extremely small. 

Its gray color indicated that not more than one-half was carbon. 
The proportion of carbon carried off in the black smoke of this 
bituminous coal, would, therefore, appear to be not far from one- 
sixth of one per cent. 



APPENDIX A. 



Memorandum of agreement by and between Obadiah Marian d of 
Boston, in the County of Suffolk and Commonwealth of Massachu- 
setts, and 

the Pacific Mills, of Lawrence, Massachusetts, 
the Massachusetts Cotton Mills, of Lowell, Massachusetts, 
the Boott Cotton Mills, of Lowell, Massachusetts, 
the Naumkeag Steam Cotton Company, of Salem, Massachusetts, 
the Atlantic Cotton Mills, of Lawrence, Massachusetts, 
the Great Falls Manufacturing Company, of Great Falls, N. JL, 
the Boston Manufacturing Company, of Waltham, Massachusetts, 
the Merrimack Manufacturing Company, of Lowell, Massachusetts, 
the Salmon Falls Manufacturing Company, of Salmon Falls, IS". H., 
the Nashua Manufacturing Company, of Nashua, New Hampshire, 
the Lancaster Mills, of Clinton, Massachusetts, 
the Manchester Mills, of Manchester, New Hampshire, 
S. D. Warren & Co., of Cumberland Mills, Cumberland, Maine. 

The said corporations and manufacturers agree to make and cause 
to be made a test of the apparatus set forth and described in United 
States Letters Patent, No. 205,282, to O. Marland, dated June 25, 
1878, and Great Britain Letters Patent, No. 2553, to said Marland, 
dated June 26, 1878, in accordance with the description of said ap- 
paratus contained in said Letters Patent, at the Pacific Mills in the 
City of Lawrence, Massachusetts, under the supervision, control 
and direction of John C. Hoadley, at their joint expense and cost, 
in the manner and upon the conditions named herein. 

Said test to be made forthwith and without delay as soon as the 
said apparatus can be properly constructed and placed in operation 
at said Pacific Mills. 

Said test to be made with reference to the combustion of both 



APPENDIX A. 157 

anthracite and bituminous coals, and the device for superheating 
air as set forth in said Letters Patent or either thereof shall be ap- 
plied to the furnace or furnaces used to make said test. 

The expense and cost of said test and the apparatus constructed 
therefor shall be borne and paid by said corporations and manufac- 
turers respectively according to the number of boilers now in use 
at their mills named herein set against their names hereto respect- 
ively. 

Said test to be made and a full and complete report thereof to be 
made by the engineers and experts employed by said corporations 
and manufacturers to make said test and to be furnished in writing 
signed by said engineers and experts to said corporations and man- 
ufacturers as soon after said test is completed as said report can be 
prepared, and a copy of said report to be furnished to said Mar- 
land. 

When said John C. Iioadley shall give notice in writing to said 
corporations and manufacturers and said Marland that said test has 
been made, then it shall by the parties to this memorandum be 
deemed to be made. 

All upon the condition that not less than two hundred (200) 
boilers shall be represented by the corporations and manufacturers 
named herein. 

And the said Obadiah Marland, for himself, his executors, ad- 
ministrators and assigns, agrees to issue and grant unto each and 
every of the corporations and manufacturers herein named whose 
signatures are placed hereto, absolute license for the full term of 
said Letters Patent and all reissues and extensions thereof, without 
charge for royalty, rental or otherwise, to apply and use his inven- 
tion set forth in said Letters Patent upon and in connection with 
any and all boilers for stationary purposes which now are in use or 
which may be constructed to be used in the mills now owned by 
said corporations and manufacturers at the places named herein and 
set against their names hereto respectively. 

Said right and license by said Marland or his executors, admin- 
istrators or assigns, to be made by him or them to said corporations 
and manufacturers in due form in writing as soon as said test shall 
be made and the report thereon in writing made by said engineers 
and experts and furnished to said Marland or his executors, admin- 
istrators or assigns. 

In consideration of the mutual promises of the parties hereto, the 
said Marland and the said corporations and manufacturers have sev- 



158 APPENDIX B. 

erally placed their hands and affixed their seals hereto, this twelfth 
day of February, a.u. 1881. 

Signed, 
Obadiah Marland, [l. s.] 

NO. OF BOILERS. 

50 Pacific Mills, Lawrence, by Henry Saltonstall, Treas., [l. s.] 

12 Boston Mfg. Co., Waltham, by Edmund Dwight, Treas., [l. s.] 
9 Naumkeag Steam Cotton Co., Salem, by H.D.Sullivan.Treas., [l. s.] 

10 Atlantic Cotton Mills, Lawrence, by Wm. Gray, jr., Treas., [l. s.J 

18 Massachusetts Cotton Mills, Lowe. 1, by Geo. Atkinson, Treas., [l. s.] 

13 Great Falls Mig. Co., Great Falls, by A. P. Rockwell.Treas., [l. s] 
37 Manchester Mills, Manchester, by John C. Palfrey, Treas., [l. s.] 
10 S. D. Warren & Co , Cumberland Mills, [l. s.] 

9 Merrimack Mfg. Co., Lowell, by C. H. Dalton, Treas., [l. s.] 

13 Boott Cotton Mills, Lowell, by Augustus Lowell, Treas., [l. s."| 

3 Salmon Falls Mfg. Co., by H. Stockton, Treas., [l. s.] 

8 Nashua Mfg. Co., by Frederic Amory, Trea<., [l. s.] 

10 Lancaster Mills, Clinton, by James S. Amory, Treas., [l. s.] 



APPENDIX B. 

COMBUSTION OF FUEL. 

BY J. C. HOADLEY. 



TnE perfect combustion of one pound of pure carbon produces, 
it is said, heat equal to 14,500 thermal units; i &, heat enough to 
raise the temperature of 14,500 pounds of ice-cold water 1° Fah- 
renheit. No coal, no coke, consists of pure carbon. Commercial 
anthracites yield, on analysis, about tive per cent, of oxygen and 
hydrogen united in the form of water, so that the hydrogen is of 
no calorific value. There is also a varying proportion of earthy 
matter left in the furnace after combustion — in part also drawn 
into the flues and chimney — ranging from 5 to 15 per cent. The 
purer coals are apt to crumble so badly in heating, for want of the 
tenacity which a larger proportion of "ash" would give, that they 
often suffer considerable loss by decrepitation, and sifting through 
the fire into the ash-pit unburned. These causes reduce the theo- 
retical value of one pound of commercial coal (anthracite) about 
one-sixth, or from 14,500 to 12,083 thermal units. 

Each thermal unit is equal to 772 foot-pounds of work, eo that 
the perfect combustion of one pound of commercial anthracite 
coal is equal to 

12,083 x 772 = 9,328,076 foot-pounds. 
One horse-power exerted during one hour is 33,000 x 60 = 1,980,- 



APPENDIX B. 159 

000 foot-pounds; therefore, if all the work represented by the 
perfect combustion of the carbon contained in one pound of com- 
mercial coal in one hour could be converted into useful work in an 
engine, it should produce 

9328076 4tn .i , 

198QQ00 = 4.711 horse-power one hour; 

and each horse-power should require, each hour, 

1980000 A010 , . . 

9828076 = pounds of coal. 

But in fact, instead of about one-lifth of one pound, the very best 
engines require ten times as much, or two pounds per hour. Very 
good practice requires fifteen times as much, or 3.0 to 3.25 pounds ; 
and the great majority of good engines consume from fifteen to 
twenty times the above quantity — that is, 3.25 to 4.25 pounds of 
coal per horse-power per hour — and show a ratio of actual per- 
formance to the full calorific power of the fuel consumed of 5 to 6 
per cent. But this loss of from nine-tenths to nineteen-tw T entieths 
of the work represented by the combustion of coal — almost start- 
ling when contemplated for the first time — is in great measure 
irremediable in the steam engine, arising as it does from the 
physical properties of water, employed as a vehicle for the use of 
heat. The problem in the steam engine is to convert the molecular 
motion of heat into the sensible motion of ponderable masses — 
a piston, fly-wheel, etc. ; and the degree in which it is possible for 
it to accomplish this, every imperfection and every source of loss 
eliminated, is the ratio which the difference of temperature of 
initial and exhaust steam (or its "range") bears to the absolute 

T — T 

temperature of initial steam ; that is, — ^= — -, where T is the abso- 

lo 
lute initial temperature, and T t the absolute final temperature. For 
instance, if in a locomotive steam be taken into the cylinder up to 
the point of cut-off, at 120 pounds per square inch, steam-gauge press- 
ure (above a mean atmospheric pressure of 14.7 pounds) = 134.7 
pounds absolute pressure, its sensible temperature Fahrenheit will 
be 350°, and its absolute temperature 461° greater, or 350 4- 461 
= 811°. Exhausted underpressure a little greater than that of the 
atmosphere, say 15 pounds per square inch absolute pressure, its 
sensible heat Fahrenheit will be 213°, and its absolute temperature 
will be 461° more, = 213 + 461 = 674°. Now, if T = 811°, and 

T, = 674°, then ^- = 81 ^~ 674 = gj = 0.169, or say 16* 

per cent. That is, the range of temperature between initial and 



160 



APPENDIX B. 



exhaust steam being 137° Fahrenheit, and the absolute initial tem- 
perature being 811° Fahrenheit, such a steam engine, on account of 
being obliged to let the steam go while it still has a temperature 213° 
above zero Fahrenheit = 674° above absolute zero (which is 461.2° 
say, 461° below zero Fahrenheit), has within its reach, if it could save 
it all, only 16.9 per cent, of the whole work contained in the initial 
steam in the form of heat. Such an engine will in fact yield about 
6 per cent; and, dividing this 6 per cent, by the 16.9 per cent., 

we have -^ = .355, or 35.5 per cent., as the ratio of usual engine 

performance to perfect performance of a perfect heat engine, under 
the above usual conditions. 

About two-thirdsj then, of the heat work that may at least be 
striven for is usually lost. 

Where is this loss? In the engine chiefly ; but the boiler must 
come in for a share. 

Let us see what the boiler's share of this loss amounts to. Pure 
carbon perfectly burned, with just sufficient air to supply the 
requisite oxygen, wall produce mixed gases weighing 12.6 pounds 
for each pound of carbon : 

Carbon, 1.0 Carbon, 1.00 
Air, 1L6 Oxygen, 2M 
12.6 C0 2 SM ] 

Nitrogen, 8.94 j. Products. 
lSUK) J 

The specific heat of carbon dioxide is 0.216 ; that of oxygen, 
0.217; nitrogen, 0.244; atmospheric air, 0.238. It follows that 
the specific heat of all the products of combustion, with whatever 
excess of air over that chemically necessary to the complete com- 
bustion of carbon, is about 0.237, and that, to heat one pound of 
water 1° Fahrenheit, 4.22 pounds of such gaseous products must 
be cooled an equal amount. If a pound of coal were pure carbon, 
its gases would weigh, without excess of air, 12.6 pounds; with 50 
per cent, surplus, 18.4 pounds ; with 100 per cent, surplus, 24.2 
pounds; with 125 per cent, surplus, 27.10 pounds; and with 150 
per cent, surplus, 30.00 pounds. But of commercial coal only five- 
sixths is carbon. We neglect the water (or oxygen and hydrogen) 
— as the quantity, small at most, is variable, and its effect on the 
result would not justify the complication its consideration would 
cause — and simply take five-sixths of the above quantities, and 
tabulate them, with the corresponding weight of water per degree, 
and the thermal units expressed in foot-pounds. 



APPENDIX B. 



181 



TABLE I. 

GASEOUS PRODUCTS OF THE COMBUSTION OF ANTHRACITE COAL, AND THE LOSS 
CAUSED BY THE ESCAPE OF THESE CASES AT SEVERAL ASSUMED TEMPERA- 
TURES ; WITH JUST SUFFICIENT AIR FOR PERFECT COMBUSTION, AND WITH 
VARIOUS DEGREES OF SURPLUS, 50, 100, 125, AND 150 PER CENT. 



Excess of air 


Weight of the 




Thermal 
uuits ex- 
pressed in 
foot-pounds, 
one thermal 
unit being 








above that 


gaseous pro- 


Correspond- 








chemically 


ducts of com- 


ing weight of 


Total for 300 Q 


Total for 400° 


Total for 500° 


necessary for 


bustion of 


water which 


above ex- 


above ex- 


above ex- 


combustion 


the carbon in 


could be 


ternal air. 


ternal air. 


ternal air. 


of carbon, per 


one pound 


heated 1° by 








cent, of the 


of anthracite 


cooling these 


Foot-pounds. 


Foot-pounds. 


Foot-pounds. 


necessary 
quantity. 


coal, 5-6 of 
coal. 


gases 1°. 


pounds. 








1 


2 


3 


4 


5 


6 


7 






Thermal 












Pounds. 


units. 


Foot-Lbs. 


Foot-Lbs. 


Foot-Lbs. 


Foot-Lbs. 





10.50 


2.4881 


1,921 


576,300 


768,400 


960,500 


50# 


15.333 


3.6335 


2,805 


841,500 


1,122,000 


1,402,500 


100# 


20.166 


4.7788 


3,689 


1,106,700 


1,475,600 


1,844,500 


125f£ 


22.583 


5.3515 


4,131 


1,239,300 


1,652,400 


2,065,500 


loOfe 


25.000 


5.9242 


4,573 


1,371,900 


1,829,200 


2,286,500 



I have made the divisions above mentioned for various tempera- 
tures, ranging from 300° to 700° above the external air, and have 
tabulated the result in the following table : 

TABLE II. 

RATIO, PER CENT., OF THE HEAT CARRIED OFF BY THE GASEOUS PRODUCTS 
OF COMBUSTION TO THE TOTAL CALORIFIC POWER OF EACH POUND OF COAL ; 
WITH VARIOUS DEGREES OF EXCESS OF AIR, AND AT VARIOUS TEMPERA- 
TURES OF THE ESCAPING GASES ABOVE THE EXTERNAL AIR. 



Excess of air 
above that chemic- 
ally necessary for 

combustion of 

carbon, per cent, of 

the necessary 

quantity. 


EATIO OP LOSS TO TOTAL CALORIPIC POWER. 
PER CENTUM. 


Temperatures above external air. 


300° 

2 


400° 


5 0° 


600° 


700° 


800° 


75° 


1 


3 


4 


5 


6 


7 


8 




50% 
100# 
125# 
150$ 


6.18 

9.02 

11.86 

13.29 

14.71 


8.24 
12.03 
15.81 
17.72 
19.61 


10.30 
15.04 
19.77 
22.15 
24.52 


12.36 

18.04 
23.72 
26.58 
29.42 


14.42 
21.05 
27.67 
31.01 
34.32 


16.47 
24.06 
31.63 
35.44 
39.23 


1.55 
2.25 
2.97 
3.32 
3.68 



11 



162 APPENDIX B. 

Since, as we have seen, the total calorific power of the five-sixths 
of a pound of carbon in one pound of commercial coal is five- 
sixths of 14,500, equal to 12,083 thermal units of 772 foot-pounds 
each, equal to 9,328,076 foot-pounds, the numbers in the columns 
5, 6, and 7 of Table I., divided by 9,328,076, will give the respect- 
ive ratios of loss from this cause in each case. 

Doubts may be entertained as to so large an excess of air as 150 
per cent, occurring in practice. In fact, it is very common. It is 
not easy to carry on complete combustion by means of natural 
draft with less than 100 per cent, excess — i. £., double the 
necessary quantity — reckoned as it usually is at 12 pounds of gases 
absolutely necessary per pound of coal, as if coal were entirely 
composed of carbon. Now, 25 pounds of gaseous products for the 
combustion of one pound of anthracite coal containing only five- 
sixths of a pound of carbon, and producing, with no excess of air, 
only 10.5 pounds of gases, is equal to (&% = 2.38) 138 per cent, sur- 
plus air. Experiments to ascertain the composition, volume, and 
temperature of the gases from 17 boilers, burning good anthracite 
coal at a known rate, with great care, and under most favorable 
conditions of draft, grate area, rate of combustion, area of heat- 
ing surface, and general management, gave, by analysis, carbon 
dioxide (no monoxide), nitrogen, and free atmospheric air — the 
latter being one-half of the whole. A check upon the accuracy of 
these results was found in the temperature of the furnace. This 
should be, with double supply of air, about 2,600° Fahrenheit. It 
was found to be a little less, about 2,400°. In my opinion, it is 
understating rather than overstating the matter to say that the 
average of good practice would show a double supply of air. 

If we take as the most common boiler pressure in stationary 
boilers 80 pounds per square inch above the atmosphere — say 95 
pounds absolute — its temperature, 324° Fahrenheit, will be that of 
the cooling surface to which the hot gases are exposed. In strict- 
ness, the temperature of the outside of the boiler plates will be 
higher than this, as 324° must be about their temperature inside, 
and the transmission of heat from without implies a higher tem- 
perature on the outer surface. Data exist for the computation of 
this exterior temperature under given conditions; but the compu- 
tation is unnecessary here. It is probable that there can be no 
active transmission of heat from the gases without to the water 
within a boiler, with less than 75° difference of temperature within 
and without, which will include the difference in the two sides of 









APPENDIX B. 163 

the plates. Professor Dwelshauvers-Dery, in an article published 
in the Revue Industrielle des Mines, of which a translation 
appears in Yan Nostrand's Engineering Magazine for February, 
1880, estimates this difference at 91° C. = 164° Fahrenheit, which 
seems to me excessive ; but 75° is probably quite within the mark. 
Observation of a pyrometer in the smoke-box of a return-tubular 
boiler at all stages of the fire has satisfied me that in excellent 
boilers, well fired, having a ratio of heating surface to grate area 
as large as 36, the temperature of the escaping gases rarely, if ever, 
falls lower than 75° above the temperature due to the steam press- 
ure, except when the fire-doors are open, and there is great and 
unusual excess of air admitted. Adding 75° to the temperature 
corresponding to 80 pounds steam-gauge pressure, 324°, we have, 
say, 400° as the lowest practicable temperature of escaping gases. 
This will be confirmed by the best practice under favorable con- 
ditions; and the actual temperature will range through a low 
average of 500° and a high average of 600° up to 800° or over;* 
in some extreme cases going up to high incandescence, or over 
1,000°. 

How much of this loss can be saved and returned to the fire ? 
By the Marland plan of passing the gases after their escape from 
the boiler through thin passages, the thin walls of which are in 
contact on their opposite sides with air for supplying combustion, 
entering with a current flowing in a direction opposite to that of 
the gases, the final temperature of the cooling surfaces becomes 
that of the external air, say, as an approximate mean, 60° Fahren- 
heit, to which the temperature of the gases may be made to ap- 
proximate as closely as to the temperature of the water in the 
boiler, say within 75°, making their ultimate temperature, on 
release, 60 + 75 = 135°. This is not too hot for discharge through 
a Root blower, while it is too cool to give efficient draft in a 
chimney. At this temperature the ratio of irrevocable loss becomes 
one-fourth as much as at 300° above outside air, say, for double 
supply of air (100 per cent, surplus), 2.97 per cent. 

I have set the several ratios in an additional column at the right 
hand of Table II., column 8. Taking now the ratios of loss, with 
100 per cent, surplus air, from Table II., and subtracting from each 
one this final loss, we have 



164 



APPENDIX B. 



TABLE III. 

RATIO, PER CENT., OF SAVING TO BE EFFECTED BY O. MARLAND'S SMOKE-COOL- 
ING AIR-HEATER, AT 100^ SURPLUS AIR SUPPLY. 





TEMPERATURES OF GASES ON ESCAPING PROM BOILER ABOVE EXTERNAL 
AIR. 




300° 


400° 


5u0° 


600° 


700° 


800° 


1 


2 


3 


4 


5 


6 


7 


First loss 

Final loss 


11.86 
2.97 


15.81 
2.97 


19.77 

2.97 


23.72 

2.97 


27.67 
2.97 


31.63 
2.97 


Actual saving 


8.89 


12.84 


16.80 


20.75 


24.70 


28.66 



It appears, then, that under ordinary circumstances from 16 to 
20 per cent, of the total quantity of heat produced by the combus- 
tion of anthracite coal can certainly be saved and returned to the 
furnace by the Marland apparatus, judiciously arranged and pro- 
portioned ; that in no circumstances can such saving fall so low as 
10 per cent. ; and that it will often be 25 per cent., and may, in ex- 
treme cases, reach 30 per cent. 

The rate of evaporation per pound of coal from feed water at 60°, 
under 80 pounds steam-gauge pressure, say 324°, is certainly, in 
genera], below 8 pounds. Indeed, 8 pounds of dry steam is a fair 
result, 8.25 pounds a good result, 8.5 pounds very good, and 9.0 
pounds about the best usually attainable, being rather over 10,000 
thermal units, which corresponds to 69 per cent, of the full calorific 
power of carbon, and is, for coal of five-sixths carbon, a high result. 

If we take, as we properly may, 8.5 pounds of water evaporated 
into dry steam of 80 pounds steam-gauge pressure from feed water 
of 60°, with one pound of anthracite coal of five-sixths carbon, as cor- 
responding to an air supply of 100 per cent, surplus, and escaping 
temperature of gases of 400° above external air, the apparatus, in 
effecting a saving of 12.84 per cent., would add to the evaporation, 
say, 12.84 per cent, of 10.8 = 1.4 pounds, making (8.5 + 1.4) 9.9 
pounds ; 10.8 pounds being the full evaporating power of such coal 
under the given conditions. To about this degree. of efficiency, or to 
nearly or quite 10 pounds of water per pound of five-sixths coal from 
water of 60° to steam of 324° (80 pounds steam-gauge), this appa- 
ratus should be able to bring all good boilers, with whatever excess 



APPENDIX B. 165 

of air, or at whatever (reasonable) degree of beat, the gases were al- 
lowed to escape from tbe boiler. Not only will this apparatus re- 
store to the furnace a large part — from four-fifths to eight -ninths of 
the heat otherwise inevitably lost ; not only will it serve as a "heat- 
trap " to arrest and restore the loss otherwise inevitable by admis- 
sion of cold air at the doors while firing and clearing out fires, and 
by the neglect or unskillfulness of firemen — it will also, I have no 
doubt, increase the rapidity of combustion, and so enable complete 
combustion to be carried on with a smaller quantity of air, i. e., 
with less excess over the quantity chemically necessaiy. 

It is true that by heating air from 60° up to 385° (that is, up to 
400° above the temperature of external air less 75° of final differ- 
ence), or from 521° to 846° absolute temperature, its volume will 
be increased in the ratio of these latter numbers, as 1 to 1.624, or 
about one to one and five-eighths : eight (8) cubic feet of air in the 
atmosphere will occupy thirteen (13) cubic feet in the pipes con- 
ducting it to the fire, whether above or below the grates. 

Of course its density is in the same inverse ratio. Thirteen 
cubic feet of the heated air (385°) must be admitted to the fire and 
to contact with glowing fuel, in order to introduce as much oxygen 
as would be contained in eight cubic feet of the cold air (60°). 

Equally, of course, the entering velocity must be greater in the 
some proportion, since the aggregate area of all the orifices through 
the grates and fuel may be regarded as constant. 
This has been urged, sometimes most strenuously, as an objection 
to heating air before its introduction to the fire. The objection 
seems to me to rest on a partial view of the conditions of air- 
admission. It may be conceded that cold air in necessary quantity 
will enter the ash-pit, and will pass through the interstices of the 
grates, with less velocity than will the same quantity of heated air. 
But in these passages the area is (or always may be) amply large, 
and the velocity moderate. It is also true that, on entering the 
lower stratum of fuel, the velocity of the heated air will be the 
greater. But the very first effect of the chemical union of any part 
of the oxygen with any part of the carbon is to heat the gases as- 
sociated with such oxygen — that is, its associated nitrogen and 
the atmospheric air yet containing its oxygen, together with 
the carbon dioxide resulting from such union or combustion — to 
the full extent to which the entire heat of combustion can raise the 
given mass of gases. This will be, approximately, the temperature 
of the furnace, a little modified, probably a little increased, by the 



166 APPENDIX B. 

subsequent union of further portions of oxygen with new portions 
of carbon encountered during the farther progress of the mixed 
gases through the fuel, until they emerge, further de-oxygenated and 
further loaded with carbon dioxide, at the surface of the fire. If 
there is not, as there need not be, any carbon monoxide, the gases 
will be at their hottest and at their greatest volume on emerging 
from the surface of the fire. 

Any further admission of air will only cool them by dilution. 
If their temperature be now 2,500° Fahrenheit = 2,961° absolute, 

2961 
their volume will be -™- = 5.7 times that of air of tempera- 
ture 60°, and -~^ = 3.5 times that of air of temperature 385°. 

Now it is the volume of the gases at their final emergence from 
the interstices of the fuel that determines their flow — determines 
the force of draft or blower required to produce that flow. The 
expansion, which of necessity takes place in the most confined 
space — namely, in the interstices of the fuel — acts equally in all 
directions. Although all in motion upward through the fire, its up- 
ward portion, being most expanded, is moving more rapidly than its 
less expanded lower portion ; and its expansive force, acting down- 
wardly, simply retards the upward flow of entering air. Lateral 
expansion aids in bringing fresh oxygen into contact with uncon- 
sumed carbon. Upward expansion aids, and downward expansion 
retards, the draft. Now it is plain that this effect must be the 
greater, the greater the degree of expansion which takes place 
within the interstices of the fuel. 

With air supply at 60°, it is 5.7-fold. With equal air supply (by 
weight), at 385°, "it is 3.5-fold. 

This difference is in the right direction to compensate, as far as 
it goes, for the greater force required to introduce the heated air 
with its greater volume and higher velocity, and certainly does com- 
pensate for it to some extent. My impression is, that it exactly 
balances the initial resistance ; that the diminution of resistance to 
final expansion is an exact equivalent for the resistance encountered 
on entering ; but this opinion is based on general dynamic consid- 
erations, and is not the result of special investigation. Certainly it 
cannot be far wrong. 

Of the higher resulting temperature of the gases, there can be 
no question. 

Nor can it be questioned that combustion will be more rapid. 






APPENDIX B. 167 

Carbon (a solid) and oxygen (a gas) unite at all temperatures 
usually met. Anthracite coal wastes, in the open air, by slow com- 
bustion — so slow that the resulting heat, which is exactly the same 
as if the combustion were more rapid, is dissipated by radiation 
and the convection of the air. The rapidity of combustion is aug- 
mented with the rise of temperature, and is very great at high incan- 
descence. Now, the temperature of the oxygen is no less impor- 
tant than that of the carbon : the higher the sum of their temper- 
atures, the more rapid their union. So far as the associated gases 
are concerned, their higher temperature only serves to communi- 
cate more heat to the mass, or (which comes to the same thing) to 
abstract less from it. 

Combustion being more rapid — being carried on with greater 
avidity — it seems certain that a smaller excess of air w T ill be prac- 
tically required ; and, although the Marland apparatus diminishes 
the final loss from excessive air supply, it does not entirely remove 
it, since it must release the gases about 75° above the temperature 
of surrounding air. It also costs something to pass air through a 
blower or a chimney; and the less of it necessary, the better. 

Grates of ordinary form could not endure a temperature of 400° 
or 500° in the ash-pit ; but water grates are well known, and en- 
tirely available. 

This device of Mr. Marland is an application of the well-known 
and firmly established principles of the Siemens regenerating fur- 
nace, by means of appropriate apparatus, to the conditions of such 
furnaces as those of steam boilers, and, if judiciously applied and 
worked out, should be as successful in its sphere as the Siemens 
furnace is in metallurgy. 

This apparatus is particularly well adapted to the combustion of 
anthracite coal. Prideaux justly says {The Economy of Fuel, 
edited by D. K. Clark, New York, D. Yan Nostrand, 1879, Part 
II., p. 211), " The less the quantity of hydrogen present, as with 
anthracite, the greater will be the chance of being able to seize the 
economic advantages attendant upon the increased quantity of heat 
attainable by the use of hot air, without having this heat so diluted 
as to make the temperature inefficient." 

There can be no doubt that the heat to be returned to the fur- 
nace would several times exceed that necessary to make the power 
required to drive the exhausting fan, to the operation of which the 
final temperature of the gases presents no objection. No damage 
would probably be done to the plates of the air passages of this 



168 APPENDIX C. 

apparatus by the heat of the entering gases in any admissible cir- 
cumstances. Such gases are usually received from the flues of re- 
turn-flue or return-tubular boilers, in plate-iron smoke-boxes, which 
prove as durable as other parts of the boiler and its appurtenances. 

The passages are so divided that each one is thin, and the ex- 
posed surface is large, so that the temperature would fall rapidly, 
and thin plates must prove durable. The use of an exhaust fan 
will produce an inward draft at all oriflces or leaks, which will 
merely increase, in some small but probably insensible degree, the 
load on the blower, but will, on the other hand, keep the incoming 
air free from carbon dioxide and nitrogen, and the fire-room free 
from noxious gases. 

In the construction of new works the outlay for the Marland ap- 
paratus will be, or at least may be, largely offset by saving in the 
cost of a chimney. 

If this apparatus can be successfully applied to marine engines, 
the gain by reduction of coal cargo, and by the increase of paying- 
freight carrying-capacity, is too obvious to require comment. 

The arrangements for cleaning out the smoke passages seem to 
be convenient and efficient. The whole apparatus bears marks of 
thoughtful study, and seems to me to promise results worth some 
effort and expense to put to the proof of practical working. 



APPENDIX C. 



When these experiments were undertaken, it was assumed that 
certain letters patent granted to Obadiah Marland, described in 
Appendix A, might be considered valid. Subsequent investigation 
disclosed letters patent of Great Britain of earlier date, which 
seemed to limit, at least in some degree, the scope of the claims in 
said Marland's patents. Without expressing any opinion upon the 
effect of such apparent anticipation, I have thought it proper to 
call the apparatus used in these experiments (which differed in 
many respects from Marland's), by the general name of a " Warm- 
Blast Apparatus." J. C. H. 



INDEX 



A 

PAGE 

Absteactoe, for warming air entering the furnace by heat from the escap- 
ing flue-gases . . 14 

No. 1. Principles of its construction 20 

Did not answer expectations 22 

Heat equally diffused 22 

No. 2. Improved efficiency of 24 

Method of supporting 24 

Principles and mode of construction 22 

Probable durability of 24 

Alteration of Pacific (cold-blast), boiler-setting, to warm-blast boiler No. 2. . 10 

Agitator, for calorimeter 42 

For pyrometer 48 

Air, infiltration of, through brick-work 25 

Leakage of, at doors and arch fronts 25 

Air-space in brick-work of little use 25 

Alcohol and water, use of, in anemometer 51 

Analysis of Chimney gases, days 75 

Nights 76 

Continuous 113 

Of coals, summary of 8 

Details of 73, 74 

Manner of making 88 

Anemometer, Cassella 53 

Wollaston 50 

Cork rings for packing 53 

Delicacy of 53 

Method of using 51 

Olive oil, and alcohol and water used in 51 

Aneroid barometer, incased 53 

Appendix A, Contract for making the experiments 156 

B, Combustion of fuel, by J. C. Hoadley 158 

C, Patents, 0. MarlanfTs and others 168 

Arch over boiler in brick-work of warm-blast boiler- setting No. 1 13 

Ashes and residue : first method of treating, — by grading and analysis 126 

Second method of determining, — by difference 128 

B 

Balance, chemical 55 

Barometer, aneroid, incased 53 

Mercurial 54 

Berthelot, remark upon agitators 28 



170 INDEX. 

PAGE 

Blower, power consumed in driving 15,) 

Boiler, capacity of, at various heights of water line and at various pressures. 133 

Description of 8 

Feed- water, how introduced K) 

Fire-grales 9 

Flues 9 

How supported 10 

Pacific, brick-work of setting 9 

Covering over 10 

Shells 8 

Boiler-house, ground plan of 11 

References to ground plan of 12 

Boiler-pressure by steam-gauge 129 

Boiler-setting, Pacific, cold-blast, altered to warm-blast No. 2 10 

Boiler tests usually of limited value 1 

Brick-work a reservoir of heat 149 

Permeability of, to air 25 

Radiation of heat from 134 

Transmission of heat through 140 

C 

Calorimeter 40 

Determination of heat value of 43 to 49 

Errors in pouring in and drawing out water, and of weighing 44, 45 

Calorimetric observations to ascertain the quantity of entrained water in the 

steam 90 to 104 

Probable limit of error Ill 

Reduction of 107-1 10 

Capacity of boiler at various heights of water line, and at various press- 
ures 133-136 

Carbon monoxide, experiment on the production of, by excessively rapid firing 119 

Carbon, solid, in flue gases 155 

Chemical balance 55 

Coal, kinds of, used in the experiments 8 

Method of taking and preserving samples 8 

Summary of results of analysis 8 

Details of results of analysis 74 

Combustion of fuel, pamphlet on, by J. C. Hoadlcy. — Appendix B 158 

Comparison of temperatures of warm and cold-blast boilers 83 to 88 

Condensed record of weekly experiments 60-7G 

Conduction of heat through brick-work 140 

Continuous analysis of flue-gases tl3 

Contract for making the experiments, — Appendix A 156 

Conversion of Pacific boiler into warm-blast boiler No. 2 20 

Cracks in brick -work should be carefully stopped 26 

D 

Dampers in smoke-flues 15 

Difficulty of making satisfactory experiments 3 

Duration of each experiment 6 



INDEX. 171 

E 

PAGE 

Edson's pressure recording gauge 56 

Diagrams 129 

Efficiency of boilers, maximum 126 

F 

Fire-brick, how used in boiler-setting 10 

Fire-doors and ash-pit doors should be tight 26 

Fire-grates, area of 9 

Distance from boiler 10 

Long Pacific grates unsafe, with warm-blast 19 

Water-grate tried 19 

Williams' rocking grate 19 

Flue for " superheating "air 17 

Flue-gases, continuous analysis of 113 

Flue-gases, to compute the weight of, per pound of coal burned. . . . 122 

G 

Gases, flue, continuous analysis of 113 

Geissler bulbs 55 

General summary of results 57-60 

Green's Economizer 2, 6 

Green, J. & H. G., New York 54 

H 

Hard rubber, for heat-insulator 27 

Heated air introduced by split-bridge 17 

Eoadley, J. C 150, 156, 157, 158 

Huddleston, J. S. F., Boston 54 

Hygrometer 54 

I 

Incased aneroid barometer 53 

Infiltration of air through brickwork 25 

Iron, specific heat of 34, note, 38, 39 

Isinglass panels in small doors in side- wall 15 

L 

Leakage of air around boilers 25 

Loss arising from opening doors to clean grates 19 

Losses, aggregate 126 

Attending combustion separately considered 122 

By carbon monoxide in flue-gases 125 

By heat carried off by flue-gases 123 

By hydrogen in flue-gases 125 

By vapor in the air 124 

By water in the coal 123 

M 

Marland, 156, 157, 158, 168 

McLauthlin, Geo. T. & Co 150 

Mercurial barometer 54 

Method of beginning, conducting and ending tests 6 

Monoxide of carbon, experiment for the production of 119 



172 INDEX. 

O 

PAGE 

Object of these experiments 3 

Observations not continuous on all subjects at once 6 

Olive oil, use of, in anemometer 51 

Omission of wood used in raising steam before starting the tests 7 

P 

Perforated tile for admitting air above the fire 17 

Platinum, specific heat of note, 34, 35, 36, 39 

Power consumed in driving blower 150 

Prentiss, Fred. H 1, 50 

Pressure in boiler, by steam gauge 129 

Pyrometer, apparatus for heating heat-carriers 40 

Correction-table for temperature of heat carrier, only approximate. ... 34 

Correction-table, platinum 35, 36 

Correction-table, iron 38, 39 

Correction-tablo, platinum and iron 39 

Determination of heat value of 29 

Heat-carriers for 29 

Heat value of 29 

Manipulation of heat-carrier 33 

Scale of 30 

Table of corrections for temperature of water 32 

Use of 31 

Use of correction tables, platinum, iron and Pt and Fe 33 

R 

Radiation of heat from brick- work 134 

Reservoir of heat in brick -work 149 

Results, general summary of 57, 60 

Rocking grates advantageous 26 

S 

Saving by warm-blast stated at 10 to 18 per cent 2 

Solid carbon in flue-gases 155 

Specific heat, Iron. , note, 34, 38, 39 

Platinum note, 34, 35, 36, 39 

Platinum and iron note, 34, 39 

Split- bridge, for introducing hot air 17 

Space between end of boiler and brick- work at rear, how closed 13 

Subjects of investigation, by the experiments 4 

Sulphur in coal, effect of 24 

Summary of results, general 57 

" Superheating "air : 17 

Superheating-surface of warm-blast boiler No. 1, shut off at end of experi- 
ments 13 

Steam gauge 56 

Pressures, in boiler 129 



INDEX. 173 

T 

PAGE 

Temperatures : warm and cold-blast boilers compared 83 to 88 

At bridge-wall 80, 81, 82 

Iu arch over warm-blast boiler No. 1 83 

In heart of fie s 78, 79 

Pyrometric measurement of 77 

Thermometers ... 54 

Transmission of heat through brick-work 140 



W 

Warm-blast boiler No. 1, description of 13 

Description of brick-work 13 

Water entrained with steam, calculation of . 105 

Williams' rocking grates 19 

Winckler apparatus for volumetric analysis of flue-gases 55 



